Thoughts of a nervous buyer

[elg]

I'm in the process of prying open my checkbook to buy a Cruzbike. I thought I'd post a summary of some of the things that have been keeping the checkbook from opening faster. I hope that this will help Cruzbike to understand their customers and (of course) give me a chance to lobby for the Cruzbike option that I want to buy.

1) Deciding between a Sofrider and a Quest.
Each has its + and - points. I'll list them for the Quest with the understanding that each applies in reverse to the Sofrider.

Compelling Quest features:
++ Disk brakes!
+ Lighter weight
+ Lower seat height
- Limited tire selection on 559
- Higher price
- Some limits on seat angle adjustment

2) Concerns about suitability in practice.
I plan to use the bike for commuting. Part of the trip is by light rail train and part is stop-and-go on the street. It seems that the height of the seat and handlebars might be a problem for the train, so I'm looking into that. For the stop-and-go all I can do is rely on testimony from Cruzbike riders that they do fine commuting in traffic.

3) Nervousness of a first-time recumbent buyer.
I've been fortunate in having had a chance to ride a Cruzbike. It went far better than the many internet postings would suggest. I was riding pretty comfortably on a street with a bit of a grade in just a few minutes. Still, one can't help but wonder about how the bike will be for stop-and-go commuting. However, I tried a fairly nice DF commuting bike yesterday at a LBS, and it convinced me that a recumbent is the way to go.

4) Wishes for more options.
I see the Sigma with its SRAM i-motion 9 and can't help wondering why that hub is not an option on any of the FWD bikes. I live in a hilly area, so the wide gear range and good shifting under load of the i-motion are extremely appealing. Particularly if I'm buying the higher-end signature design, the Quest, why can't I get the nice drivetrain? And if I buy today, will that option that I wanted so much be offered next week?

Since I'm the sort who's always willing to try something new if it seems to have advantages, (and I suspect that all Cruzbike buyers are like this), I wonder why the idea of replacing the chain with a carbon fiber belt isn't on the Cruzbike radar. That would have a marketing sex-appeal that no RWD recumbent could match. When I've shown the Cruzbike to friends who are avid cyclists they've all commented on the "busy" front end. A carbon belt + i-motion drive would have a very clean, simple, and elegant look.

With all of those things weighing on my mind, I'm settling on a Quest 559 and ferociously wrestling with my checkbook. If the i-motion option was available, with either chain or belt, then I think I could easily pin my checkbook and extract the requisite money. As I said, given that Cruzbike is already sourcing the i-motion for the Sigma, I find it difficult to understand why it's not offered on the FWD bikes that are Cruzbike's signature product.

 

[bokes]

Elg,
I'm with you all the way. I want a Quest with an IGH & belt drive too. I don't think it should be too hard to make a front boom tube that has an eccentric bottom bracket, which should take care of tensioning the belt. The bike already has a huge head start by having a removable chainstay, for getting the belt in the front triangle.
I'm too disappointed that the Quest is not available as a bare frameset. I would have bought one by now, but I don't want to get stuck with a pile of components I don't want.
But, to balance all this whining, I'd like to appreciate and thank John & Cruzbike for designing and providing all they've done already. I'm a much happier cyclist with my Silvio than I'd be without one.

 

[elg]

Bokes

Building my own is one option. As you say, they don't sell the Quest frameset, so I'd have to settle for a Sofrider or even a conversion. There would also be costs involved in getting the various components retail that Cruzbike wouldn't face if they sold the whole bike. Looking at the Sigma, it appears that they could use that rear wheel to make a IGH Quest.

Trying to get all the way to a belt drive seems to be a problem for a home-built. The main belt maker, Gates, seems to sell it only into the OEM channel. That's a pity, since most OEMs can't manage the split chainstay. Any Cruzbike owner has got that covered, but can't buy the belt drive. It's a funny world we live in...

 

[John Tolhurst]

I really appreciate this feedback, elg, thank you. I'd like to do most of what you suggest. Our constraints are that to provide a bike at the prices we do means ordering at least 100 at a time, of a fixed specification. If we went to a custom build service in the US, lots of customer options would open up and so would the price. Just as a price reality check, the bike friday folder cost over USD3000, was complex and in reality a pretty slow bike due to the joints in the structure between pedals and rear wheel, but you could have it with just about any specification imaginable. Cruzbike Inc. has taken the view that its better to give the best spec we can, keep the price reasonable and then allow customers after they've ridden the bike a while to decide which upgrades best suit their actual needs. Even if you completely rebuilt the bike at your local bike shop, you'd likely have change from USD3000. This is the production/economic reality of being a small niche product manufacturer and does fall short of what one might expect of companies that supply bikes in the tens of thousands.

I agree a belt driven internally geared hub would be real nice. What you could do without too much expense is fit a SRAM 3x9 hub, going to a single at the front (52 teeth on the Quest 451 and 42 or 44 on the Quest 559) with no front derailleur and for a weight penalty of less than a pound.

 

[elg]

John,

Thanks for the reply.

I don't really think of what I'm looking for as a "custom bike". The IGH is a pretty popular option. I don't know, however, how you go about getting your bikes built. If it's the building that's a problem I'd be happy to get a box of parts and handle the assembly on my end. If the 100 bike lot is for part sourcing purposes then I guess that's a show-stopper.

I may go the route of customizing, but I'm reluctant to do it with a Quest because of all the throw-away involved. I'd build on a Sofrider frame or, less happily, some other conversion.

 

[Doug Burton]

Hi Folks,

The SRAM I9 works best with a horizontal dropout and a tensioning device.

The Sigma dropout is designed to take the I9 and has snail cams to tension the chain. A very elegant, designed-in solution.

The Quest BB shell is not large enough to accept an eccentric BB and otherwise you'd need a tensioner, ala "single-ator". The vertical dropout in the front fork isn't well-suited to the I9 because of the hub's need to transfer torque to the frame through some type of anchor, be it a torque arm or keyed washer. Keyed washers don't get very good purchase in a vertical dropout, and the torque arm doesn't mate well with our suspension due to the cyclic effective change in fork leg/chainstay angle.

The I9 hub won't accept a belt drive in our fork due to the width of the belt and drive pulley. I also would need to assess the efficiency of a belt drive vs. chain before I'd recommend it.

There's a lot of engineering required to make these changes work on a commercial basis, particularly with supplier quantity requirements and the work necessary to maintain relationships with the suppliers over multiple design changes. And the Quest is selling well in its current configuration.

The 3x9 hub is a good option if you want the bike to have a clean front end.

Best,

Doug

 

[elg]

Doug,

I can't thank you enough for the detailed info. The SRAM 3x9 is a definite possibility.

I've found a couple of products which might help with a full IGH. They are eccentric BB inserts that fit a standard BB and take standard cranksets. One is German and pretty spendy while the other is Canadian made and a bit cheaper. Here are the links.

http://www.forwardcomponents.blogspot.com/

http://www.trickstuff.de/index.php?p=d110de1

Also, would the torque arm work OK if it was attached to the chainstay instead of the fork? At least that way it would always be at the same angle to the chain.

Again, thank you very much for the detailed technical info. I will end up with a Cruzbike in the near future, the only question is which one and what, if any, mods I might make.

 

[Manalive]

Re. torque arm fixing to chainstay - this will give problems with both the suspension and the leg-length adjustment! Reason: the chainstay pivots aren't colinear with the axle.

Those eccentric BBs look a neat idea!

 

[JonB]

I was there 2 years ago, i am happy that i bought my cruzbike.

elg wrote: 1) Deciding between a Sofrider and a Quest.
Each has its + and - points. I'll list them for the Quest with the understanding that each applies in reverse to the Sofrider.

Compelling Quest features:
++ Disk brakes!
+ Lighter weight
+ Lower seat height
- Limited tire selection on 559
- Higher price
- Some limits on seat angle adjustment

I have disk brakes on my Freerider.
I am sure schwalbe.com has some tires for you.

elg wrote: 2) Concerns about suitability in practice.
I plan to use the bike for commuting. Part of the trip is by light rail train and part is stop-and-go on the street. It seems that the height of the seat and handlebars might be a problem for the train, so I'm looking into that.

I dont think the seat is a problem. The handlebars might, but just cut them to be less wide. Or get some folding. It will affect steering though, but you can learn that. I was just at Cycle Vision 2010 this weekend, and saw a racer in the velodome on a low recumbent with a slim handlebar. And ontop of that he only drove with one hand at high speeds. And he even overtook overs.

elg wrote: For the stop-and-go all I can do is rely on testimony from Cruzbike riders that they do fine commuting in traffic.

It does work fine, i do it every day, lots of red lights. It is not a problem.

elg wrote: 3) Nervousness of a first-time recumbent buyer.
I've been fortunate in having had a chance to ride a Cruzbike. It went far better than the many internet postings would suggest. I was riding pretty comfortably on a street with a bit of a grade in just a few minutes. Still, one can't help but wonder about how the bike will be for stop-and-go commuting. However, I tried a fairly nice DF commuting bike yesterday at a LBS, and it convinced me that a recumbent is the way to go.

Recumbents sure are more comfortable. As for stop and go. At red lights i click out, put one leg down and leans slightly towards that. Or if it is a red light that takes longer time, i click out with both, sit up straight with both feet on the ground.

 

[JonB]

Doug Burton wrote: The Quest BB shell is not large enough to accept an eccentric BB and otherwise you'd need a tensioner, ala "single-ator".

I think the tensioning could also possibly be done by a single free spinning "wheel/ring" which is larger than the front "chainring" and rear "sprocket". It will be kept in place by the forces acting on it. I have seen such tensioners with both belts and chains.

Doug Burton wrote: The vertical dropout in the front fork isn't well-suited to the I9 because of the hub's need to transfer torque to the frame through some type of anchor, be it a torque arm or keyed washer. Keyed washers don't get very good purchase in a vertical dropout, and the torque arm doesn't mate well with our suspension due to the cyclic effective change in fork leg/chainstay angle.

I sort of ran into the same problem with my Rohloff hub. I bought it used and it came with a long torque arm which i was supposed to attach to the chainstay? I didnt like that idea. See the long torque arm here http://www.rohloff.de/en/info/faq/faq_detail/archive/2005/07/july/article/Why_is_the_torque_arm_so_long/index.html

Luckily Rohloff had another solution. I used an axle plate along with a Rohloff Speedbone which is mounted to the disk brake tabs. See axle plates here http://www.rohloff.de/en/info/faq/faq_detail/archive/2005/07/september/article/Axle_plates/index.html and SpeedBone here http://www.rohloff.de/en/products/speedhub/speedbone/index.html

This gives torque support and works with quick release. To keep the chain tensioned i do have a single-ator. At first i just used the rear deraillure that the bike came with. But i didnt like the 2 wheels, i wanted 1 wheel against the chain.

Doug Burton wrote: The 3x9 hub is a good option if you want the bike to have a clean front end.

I dont agree that the 3x9 hub gives a clean front end. It is still a deraillure.

 

[Manalive]

JonB wrote: I think the tensioning could also possibly be done by a single free spinning "wheel/ring" which is larger than the front "chainring" and rear "sprocket". It will be kept in place by the forces acting on it. I have seen such tensioners with both belts and chains.

I'm picturing a sprocket that isn't attached to anything, floating in space, held up by the chain tension, spinning with the chain? Very cool, if slightly alarming, idea! But won't it interfere with the chainstay...

 

[JonB]

Manalive wrote:

JonB wrote: I think the tensioning could also possibly be done by a single free spinning "wheel/ring" which is larger than the front "chainring" and rear "sprocket". It will be kept in place by the forces acting on it. I have seen such tensioners with both belts and chains.

I'm picturing a sprocket that isn't attached to anything, floating in space, held up by the chain tension, spinning with the chain? Very cool, if slightly alarming, idea! But won't it interfere with the chainstay...

You can see a stationary movie of what i ment here http://ia311025.us.archive.org/0/items/6thEuropeanSeminarOnVelomobileDesign-ShortExaminations/6velomobile_seminar_2wheel_homebuild_recumbent_2Mbit_PAL_DVD_CCBY_512kb.mp4?6thEuropeanSeminarOnVelomobileDesign-ShortExaminations/6velomobile_seminar_2wheel_homebuild_recumbent_2Mbit_PAL_DVD_CCBY_512kb.mp4

It might and might not interfere. I was actually thinking that you stick the chainstay through the "chainring".

 

[bokes]

John,
I can understand why you don't offer an IGH Quest model from the reasons you stated, However I don't see how offering a Quest frameset, or an eccentric BB boom accessory, would effect your current business model. It would just give us buyers (and DIYers) more options.

Doug,
Can you please explain what you meant when you said,
"Keyed washers don't get very good purchase in a vertical dropout"
I'm using keyed washer with an Alfine in a vertical dropout on my upright commuter with no issues, how would the situation be different on the Quest?

 

[Doug Burton]

bokes wrote:
Doug,
Can you please explain what you meant when you said,
"Keyed washers don't get very good purchase in a vertical dropout"
I'm using keyed washer with an Alfine in a vertical dropout on my upright commuter with no issues, how would the situation be different on the Quest?

I have no direct experience with the Alfine hub. I do know that the SRAM Dual Drive II 3x9 provides and specifies the use of a keyed washer for horizontal dropouts, and a serrated external face washer for vertical dropouts. My suspicion is they intend for the axle to have a specific orientation versus the chain line or the dropout opening (the axle is flat-sided), though I confess I see no obvious logic to that. Being associated with a manufacturer, I try to use the components as precisely as specified as possible, in order to avoid introducing new failure modes that aren't covered by the component manufacturer's engineering or testing, particularly if I am working on a full up bike such as we would sell to a customer. On my personal kit bikes, not so much. Perhaps excessively conservative, but it's born out by my experiences from back when I was paid to break things.

Best,

Doug

 

[elg]

All of the great info here has helped me a lot, but also raised some further questions.

First for Doug. Do you have any opinion on the eccentric BB products that I linked to? One is spec'd to provide 15mm of adjustment. I think you once said that the change in distance from the crank to the axle is 5mm through the range of the leg length adjustment (on the Sofrider?). That leaves 10 mm. Would you think that is enough to work with for a IGH?

Also, is the fork on the Quest 559 the exact same fork as on the Sofrider? If so, what limits the tire size on the Quest?

Finally, I would love to hear opinions from anyone who has ridden both the Quest 559 and the Sofrider. Which is easier to ride? Which feels more stable at high speeds and downhill? How do you feel about the difference in BB height?

I'm trying to make up my mind on which model to purchase, so hearing from folks with experience on both would really help.

Thanks again for all the info.

 

[Doug Burton]

elg wrote: All of the great info here has helped me a lot, but also raised some further questions.

First for Doug. Do you have any opinion on the eccentric BB products that I linked to? One is spec'd to provide 15mm of adjustment. I think you once said that the change in distance from the crank to the axle is 5mm through the range of the leg length adjustment (on the Sofrider?). That leaves 10 mm. Would you think that is enough to work with for a IGH?

Also, is the fork on the Quest 559 the exact same fork as on the Sofrider? If so, what limits the tire size on the Quest?

Finally, I would love to hear opinions from anyone who has ridden both the Quest 559 and the Sofrider. Which is easier to ride? Which feels more stable at high speeds and downhill? How do you feel about the difference in BB height?

I'm trying to make up my mind on which model to purchase, so hearing from folks with experience on both would really help.

Thanks again for all the info.

The Q559 tire size is dictated by the need to use the same fork for the Q451, which is designed to pack into a Samsonite F'Lite suitcase. This limits the fork leg length, and lowers the fork crown height, thus requiring a 1" 559 tire. Which is bloody fast, by the way, and not a problem due to the suspension.

Part of the issue with the IGH is that the chainstay length effectively changes a little as the suspension cycles, as Manalive mentioned (that's the beauty of this forum). I don't know how prone this will make the chain to derailing on rough surfaces, and I really can't be sure that 15mm adjustment range is adequate because of that.

I'm reluctant to recommend expensive parts I haven't worked with, such as these eccentric BB carriers. If you buy the bearings, BB axle and eccentric carrier we're talking about $250 after it's all shipped, for the least expensive one.

The I-motion 9 and special shifter is about $340 after shipping. It appears to be available only in 36 hole configuration, so you'll need a new 36 hole rim (the Q559 uses a 32 hole rim/hub) and new spokes. The wheel assembly, built, tensioned, and trued, will run you about $140 on top of the hub and shifter.

You'll want to run either a 38t or 44t chainring due to the I9 gear range (306%), which will end up being smaller that the 52/42/30 crank and 11-34 cassette we specify (535%). This would cost $30-50 depending on the quality you select. I have no clue what a belt drive set would cost, and I don't think it will fit the I9 due to the width of the mechanical section of the hub. I think John T and I have discussed that previously among ourselves in our super secret engineering conferences 12 time zones apart.

So we're looking at an additional $750 to $800, in addition to the bike, to assemble something that might have a difficult-to-remedy flaw and will have a smaller performance envelope for the 95% of the rider capability normal distribution we have to engineer bikes for.

Jim, Maria and John have generously-funded the research and development work I've done for Cruzbike, and have been very enthusiastic and supportive when I have prototyped ideas we've had for improving all our bikes, even the conversion kit. But I could never justify this proposal on many grounds.

And I can't recommend this retrofit at all.

Sorry.

Doug

 

[elg]

Doug,

Once again thank you for the very detailed technical info. It does appear that both the static BB based tensioning and the belt drive would be troublesome on a Cruzbike FWD. I'm really surprised, though, to hear you come out so strongly against the i-motion 9 as a high cost, low value component. My interest in that IGH was really driven by the fact that Cruzbike chose it for the Sigma. Surely it can't be that terrible a value.

I recently took a test ride on a Scott Sub 10 that had Shimano Alfine gears. It was priced about the same as a Sofrider 16 speed and it had Shimano hydraulic disk brakes as well as the Alfine, with eccentric BB tensioning. The IGH certainly can't account for $800 of its $1200 price tag.

I'm just looking for simple and low-maintenance gearing for a Cruzbike FWD. I've never been that fond of derailleurs, front ones in particular. The SRAM 3x9 that both you and John T suggested looks like a good solution for cutting out one derailleur. If the i-motion can work, though, then I'd view it as more attractive. That would be true even with a chain that had a spring tensioner like the one JonB used with his Rohloff.

I really like the fact that the Cruzbike community has hackers, (of which you are, of course, the uber-hacker). I plan to settle on a frame style, Sofrider or Quest, get a bike, and then scheme about mods while I enjoy riding it.

 

[John Tolhurst]

Sigma was designed from the outset for an IGH, so it works, and we buy it in bulk with the other components, so the economics works. Neither of those critical conditions are present on the proposition to retrofit an IGH to the Quest or Sofrider.

If I designed a FWD from the outset for an IGH, then it would be structured in a way different to how it is presently. Or to put it another way, if an IGH FWD is where I wanted to end up then a Quest is not where I would begin - I would need to clear the drawing board.

Thanks for pursuing the concept, its worthwhile to lay out the thinking that has gone on behind the scenes!

 

[Doug Burton]

elg wrote: Doug,

Once again thank you for the very detailed technical info. It does appear that both the static BB based tensioning and the belt drive would be troublesome on a Cruzbike FWD. I'm really surprised, though, to hear you come out so strongly against the i-motion 9 as a high cost, low value component. My interest in that IGH was really driven by the fact that Cruzbike chose it for the Sigma. Surely it can't be that terrible a value.

I recently took a test ride on a Scott Sub 10 that had Shimano Alfine gears. It was priced about the same as a Sofrider 16 speed and it had Shimano hydraulic disk brakes as well as the Alfine, with eccentric BB tensioning. The IGH certainly can't account for $800 of its $1200 price tag.

I'm just looking for simple and low-maintenance gearing for a Cruzbike FWD. I've never been that fond of derailleurs, front ones in particular. The SRAM 3x9 that both you and John T suggested looks like a good solution for cutting out one derailleur. If the i-motion can work, though, then I'd view it as more attractive. That would be true even with a chain that had a spring tensioner like the one JonB used with his Rohloff.

I really like the fact that the Cruzbike community has hackers, (of which you are, of course, the uber-hacker). I plan to settle on a frame style, Sofrider or Quest, get a bike, and then scheme about mods while I enjoy riding it.

I don't mean to seem really negative. The component prices I quoted after researching were retail prices; I'm mainly anxious about someone going to all that expense and coming out with something I can't help them with very much. Since my job around here is to solve customer problems, I like to help folks avoid the things I can see coming before they lay out the cash. The I9 is a great hub, if you design to take full advantage of its characteristics. And it is very clean-looking when installed. I don't think the Alfine setup is $800 of the Scott Sub 10's price, but it might be more than $400. We think the Quest is priced right where it needs to be. I've checked over a Sub10 at the local REI, it's a nice bike.

The Sigma can be wicked fast with this hub; Ron Witt, who co-designed Sigma with John T after years of research, regularly beats up on John and his Vendetta prototype with the aid of a fairing and some little demon tweeks he's made to a production Sigma. It's only been recently that John has been able to pull away. Talk about competitive development, those guys are sprinting 60kph on the flats and pushing each other to go faster every week. Ron is one of those natural engineering types who does better work with a grinder and a file than I do with a milling machine.

The I9 works well on the Sigma because the Sigma was designed to use it. The Sigma also benefits from a strong steering assembly to allow you to pull on the bars much like you can on our FWD bikes.

The 3x9 has real promise on the Quest because it has a derailleur to take up the chain variance, which should combine well with the smooth anytime shifting of an IGH hub. And the SRAM 1:1 pull ratio on the derailleur makes it work very well. I hope we'll have some more info on this hub in the future.

Best,

Doug

 

[John Tolhurst]

Doug Burton wrote: .... Talk about competitive development, those guys are sprinting 60kph on the flats and pushing each other to go faster every week. ...

I'm blushing. I don't think we are that fast, but we are a couple of roughly 50 year old guys who rarely find anyone in the lycra crowd who can push us. And I mean rarely. Except for my nephew on my Sivio, he has me on toast - that's why I let him ride his own sofrider mostly.

 

[elg]

Doug, John, and everybody,

Thanks again for all your help. I decided to go with the Sofrider frame rather than the Quest. I placed my order on the phone with Maria yesterday. Had fun talking with her about how her son will be one of the basic training instructors for my nephew at the Air Force Academy this summer. Looks like he'll be calling my nephew "maggot" inside of two weeks :lol:

I went with an 8 speed Sofrider with the intention of changing the gearing later. Either I'll take your good advice and add an SRAM 3x9 or, if I'm feeling contrary and flush with cash, an i-motion 9 or even the Alfine 11 that's due out in Sept.

I'll miss out on the lighter weight of the Quest. The folding feature wasn't really important to me and, to be honest, I'm actually kind of partial to the look of the Sofrider (sorry John).

I'll, of course, be present here in the forum and I'll be interested to see whether there's ever a commuter FWD bike with an IGH and belt drive. If so then please make the fork and boom usable by the Sofrider so I can get the upgrade.