What would you do?

[Rishi@Cruzbike]

hmmm.... MTB shifters of Dropbars?

 

[anotherbrian]

I’ve dropped the chain a couple times when shifting up. Always when shifting in a rush. I figured I’d figure it out eventually, but if it’s a common problem I won’t worry about it too much.

For the OP you can use a Wolftooth RoadLink and get at least an 11-40T cassette to work with the medium cage Di2 Ultegra rear derailleur. I’m doing that on my M5CHR (and using a 53/34! on the front with Di2). I’m contemplating going back to a triple and a tighter cassette on that bike though, and back to a mechanical FD.

I am sold on Di2 (especially on RWD bikes with really long cable runs), but I have no regrets about mechanical on the S40. Maybe it’s the Dura Ace shifters, but it shifts as effortlessly as the Di2. The bike is for randonneuring and I wanted the simplest setup possible.

 

[ratz]

The more I read about the gearing of my groupset, the more I'm regretting it San Marcos CA, is quite hilly and I really should have thought it thru better.
I am considering getting the SRAM 12 speed 10-50 with a 42t chainring (if something like this combination exists).

Sigh..... I'll go over to the Trek store near me and see what they can do. I should be able to return the DI2.

I really appreciate all the great information and the experiences being shared here.

https://www.wolftoothcomponents.com/collections/drivetrain-1/products/roadlink

https://www.performancebike.com/shi...d-cassette-1140t-icsm8000140/p475248?v=458439

 

[anotherbrian]

Oh, and 26” wheels _should_ give you lower gearing than a 700x28 or 700x32 unless you go for some crazy large knobby tires, and that should at least offset the shorter cranks.

 

[GetBent]

Wow! Am I understanding this thread correctly? I can use an 11-40T cassette with Di2 just by using a Roadlink? Currently running 30/46 and 11/32, but finding 9% grades taxing.

 

[anotherbrian]

Wow! Am I understanding this thread correctly? I can use an 11-40T cassette with Di2 just by using a Roadlink? Currently running 30/46 and 11/32, but finding 9% grades taxing.

Yes though chain capacity may be a factor. I have a 6870 GS RD that I think had a published capacity of 37T. The 8050 GS looks like it is 2 better at 39T.

An 11-40 has a 29T difference, so you aren’t left with much range/difference on the chainrings, though Shimano’s published capacity may be conservative. I know on my M5CHR I get some benefit from the long chain drooping, but you won’t get that at all on a Cruzbike.

 

[Rishi@Cruzbike]

https://www.wolftoothcomponents.com/collections/drivetrain-1/products/roadlink

https://www.performancebike.com/shi...d-cassette-1140t-icsm8000140/p475248?v=458439

Ordered em!!! I was told to get the Roadlink DM for the R8050 RD.

Frameset is here. I decided to have a local bike shop put it together, cause I want to ride it as soon as I can. I'll build the next one

 

[Rishi@Cruzbike]

New question

Does the DI2 software need to be fooled into working with, Roadlink modded, 11-40T and R8050 RD for Syncro Shift?

 

[Rishi@Cruzbike]

I don't see any information on what the max bike+rider+gear weight capacities for the CB bikes are. I'd like to know for the S40 and T50. Planing on making an electric T50 too

 

[ratz]

Wow! Am I understanding this thread correctly? I can use an 11-40T cassette with Di2 just by using a Roadlink? Currently running 30/46 and 11/32, but finding 9% grades taxing.

correct but talk to wolf they will guide you through the nuances.

 

[ratz]

New question

Does the DI2 software need to be fooled into working with, Roadlink modded, 11-40T and R8050 RD for Syncro Shift?

nope.
in the end it is just a 11 position device. not sure if there are limts to the tooth counts you can enter. but all that matters is the ratios if you want to use syncro

 

[Rishi@Cruzbike]

Hmmm..... 34-50T and 11-40T produces the gear ratios below. I see a good way to use Full or Semi Syncro Shift.

 

[anotherbrian]

Hmmm..... 34-50T and 11-40T produces the gear ratios below. I see a good way to use Full or Semi Syncro Shift.

View attachment 7775

Be aware the Ultegra medium cage doesn’t have enough capacity to handle little-little (and probably up to little-medium). You probably want the chain long enough to handle big-big unless you can explicitly block that combo (or are very diligent about never shifting there, with penalty being you tear your derailleur off if you forget).

 

[anotherbrian]

Be aware the Ultegra medium cage doesn’t have enough capacity to handle little-little (and probably up to little-medium). You probably want the chain long enough to handle big-big unless you can explicitly block that combo (or are very diligent about never shifting there, with penalty being you tear your derailleur off if you forget).

On my S40 I am using the 50/34 and 11-40T combo but using an XT 8000’ish MECHANICAL derailleur (with a different WolfTooth component to allow road shifters).

 

[Rishi@Cruzbike]

Be aware the Ultegra medium cage doesn’t have enough capacity to handle little-little (and probably up to little-medium). You probably want the chain long enough to handle big-big unless you can explicitly block that combo (or are very diligent about never shifting there, with penalty being you tear your derailleur off if you forget).

I've read that. I'm not good at remembering what gearing I'm at, and by using the R8050 GS + Roadlink DM + Shimano XT M8000 11-40T + Full Syncro + Garmin device to see my gearing, I'm hoping to stop just that from happening. Being in the wrong gear takes a lot of the the fun out of bicycling for me.

 

[anotherbrian]

I've read that. I'm not good at remembering what gearing I'm at, and by using the R8050 GS + Roadlink DM + Shimano XT M8000 11-40T + Full Syncro + Garmin device to see my gearing, I'm hoping to stop just that from happening. Being in the wrong gear takes a lot of the the fun out of bicycling for me.

There may longer cages available in the aftermarket — they existed before the MTB Di2 groupset came. The XTR Di2 (MTB) option has a longer cage, however the prices are/were much higher than Ultegra and it required using the MTB front derailleur as well.

 

[BikeGary]

I will add one down note on spending a lot of $ on cranks, and that is I'm on my second set due to two crashes, both of which I slid quite a was on my side and the crank arms took a beating on the road.

 

[BikeGary]

2 ways:
1) they allow you to keep your knee-bend on the upstroke at, near, or maybe even more open than 90 degrees, which is better on your knees in terms of pain and wear and tear

2) they help you get the thigh and knee clearance to the handle bars that you need, while allowing you to keep your arms reasonably extended. every cm you shorten your cranks allows you to have your bottom bracket a cm further from your bars at maximum leg extension while still having your reach to the pedal where you like it; and every cm you shorten your cranks means a cm of extra thigh/knee clearance on the upstroke. this is additive: 1 cm shorter cranks effectively gives you 2cm of extra bar clearance, without losing power. (there are studies to show that shorter cranks--within limits-- don't decrease your power even though the 'lever' is shorter)
(the opposite of shortening your cranks is also true when it comes to bar clearance: for every 1cm longer your cranks are, you lose 2cm of bar clearance)

In addition, if you spin faster you will wobble less by having less pressure on the front wheel. The shorter crank arms have less leverage and thus you will want to spin more. The other advantage of the faster spinning is that it's easier on your heart as well, as each stroke is less effort. You'll be able to climb hills with less effort. (It's still not free though!)

 

[ratz]

In addition, if you spin faster you will wobble less by having less pressure on the front wheel. The shorter crank arms have less leverage and thus you will want to spin more. The other advantage of the faster spinning is that it's easier on your heart as well, as each stroke is less effort. You'll be able to climb hills with less effort. (It's still not free though!)

technically if you spin the same speed (as in speed of foot and muscle) you complete the revolution faster because the diameter is shorter. this is heavily miss understood. faster rpm on a smaller diameter is not faster legs.

 

[super slim]

I don't see any information on what the max bike+rider+gear weight capacities for the CB bikes are. I'd like to know for the S40 and T50. Planing on making an electric T50 too

The frames can take any weight, but the wheels AND tyres cannot!

For 700C to 26"(559) tyres, the max recommended load per tyre at its max tyre pressure, for Schwalbe tyres is:-
23 mm(70 kg, 145 psi), 28 mm(75 kg, 115 psi), 32 mm(90 kg, 95 psi), 35 mm(100 kg, 95 psi), 38 mm(105 kg, 85 psi), 42 mm(120 kg, 85 psi), 50 mm(130 kg, 70 psi), 60 mm(145 kg, 55 psi).

The T50 can take a 26"*2.3"(60 mm) tyre, and the S40 can take a 700c*38 or 650B*42, OR (26")559*42.

The wheel loads for all Cruzbikes, Front and Rear are very close to 50% with just the rider.
Any luggage on the rear rack goes to the rear wheel load, and approx 75% of the weight of the S40 forward rack to the rear wheel.

Finding the load rating for wheels are MUCH harder, as the hub manufacturers don't state it, and only some rim suppliers do, and they are VERY conservative!

I rode around the South Island of New Zealand, staying in Hostels, with 3 rear Ortlieb bags (20 kg total) , with two under the frame mid way between the wheels(BIG air brakes!!!), so Front wheel load 70 kgs, Rear 76 kgs, using TWE hand built wheels, 32 spoke, 26" rims, 19 mm inside, 25 mm outside, 22 mm deep and 26"*35 mm Kojak tyres(100 kg rated), with no problems.

In 2020 I hope to ride 5,100 km total, 1600 km Van supported, and the rest self supported, in USA and Canada eastern areas.
I will try to have 3 off rear ortlieb, and 1 off front Ortlieb and 4 large Ortlieb pockets(26 kgs), mounted off the rear rack, so the max DESIGN load on the rear wheel will be 97 kg, and 7 kg on the front wheel when no rider. I still have to build the stays and see if the tail wags or not, AND the front wheel ACTUALLY does not get airborne when the rider dismounts!

I am looking to build new wheels from Hope Pro 4 disk hubs with 36 hole, Ryde Andra 30 26" (559) rims as these seem to be the preferred fully loaded Tandem rear rims, and Sapim CX-Ray bladed spokes (so I can use a spoke key to stop the blade turning when tightening the nipple) in a 3 or 4 cross pattern.

Any recommendations for the 100 Kg 100 mm non drive wheel???
The drive front wheel will be the same spec, to allow for braking loads, which could reach 150 kgs, if emergency braking lifts the rear wheel off the ground with a 185 mm front disk!!!!