Short cranks

[defjack]

Just got a pair of cranks shortend to 153.Tried them out today on some decent hills and they work pretty good for me.I was getting some knee pain even with the Qrings. With Qrings and 153 I didnt get any pain at all even with some 8-9% long type hills. Jack

 

[Mark B]

defjack wrote: Just got a pair of cranks shortend to 153.Tried them out today on some decent hills and they work pretty good for me.I was getting some knee pain even with the Qrings. With Qrings and 153 I didnt get any pain at all even with some 8-9% long type hills. Jack

Jack,

Did you get those done local, or did you have Mark Stonich do those? I'm planning on putting a shorty triple on my bike, as well. I sure like the way those 155 mm RPM cranks wind up, but I can't get used to the double. Also, I want a standard 52/42/30 instead of the 50/36.

Mark

 

[WhiteSilvio]

defjack wrote: Just got a pair of cranks shortend to 153.Tried them out today on some decent hills and they work pretty good for me.I was getting some knee pain even with the Qrings. With Qrings and 153 I didnt get any pain at all even with some 8-9% long type hills. Jack

Hi Jack,
I'm curious to know if you lengthened the telescopic boom and let the BB out a little to compensate for the shorter cranks? To allow for full leg extension.
(I'm just thinking as I type, trying to decide if that is the appropriate action to take for going to shorter cranks. My initial thoughts are that is what you'd need to do.)

I sometimes get a bit sore behind the kneecap after I have been riding for an hour and a half or longer. I'm running 170mm cranks. My other problem is my hips sometimes ache a bit after a long, fairly good Silvio-cycle workout; I think I'm wearing out! :cry:
I've now covered over 3500km since mid September '08, when I started back cycling after a 15 month layoff. Haven't been on the DF bike since the beginning of August '07.
Regards, John R.

 

[defjack]

First I emailed Mark Stonich to find out what he could shorten.Then found a set of 175 105s on ebay and had the seller send them to Mark. Mark shortned them and sent to me in a day he is a good guy to deal with.I did move the boom out .I have around 60mi on them so far and they are working out just fine. Jack

 

[Mark B]

The couple e-mail conversations I've had with Mark led me to believe he's a fine individual to work with. I mean, the first question he asked was to determine what made me think I needed short cranks. I like that.

Mark

 

[Doug Burton]

We have located a reasonable set of 155mm triple cranks for decent money. I have a set for evaluation now.

The brand name is Forza, and their quality is similar to the RPM cranks I've seen. If they check out okay in use we may be able to add them as an accessory to the website. They have a nice, tight q-factor, square taper BB, and while not Campy-sweet in appearance or CF light, they should work for most folks.

I'll keep you posted on how they work out when I get the bike up and running.

Best,

 

[Doug Burton]

Update:

You can get'em retail here...

http://www.calhouncycle.com/productcart/pc/viewPrd.asp?idproduct=1725&idcategory=0

Calhoun is good folks. I've bought three bikes from them (they're in Minneapolis; I used to visit them every time I went there on business - and too frequently came back with a bike...) :? :lol:

Best,

 

[Gromit]

Mike Burrows, the well known bike designer, is a big fan of short cranks.
He suggested that I should fit 155s when he test rode my Sofrider.

 

[3WHELZ]

Here is another source. However, I have no experience with them.

http://www.pbwbikes.com/product_info.php/products_id/65?osCsid=884b5139314c26f20ccea0da253e3df9

 

[Mark B]

I have pulled in my horns on short cranks. I had a "hold on a minute" moment yesterday when I did a trial with my longer cranks. Same bike, same route, the only diffrence was the different cranks. I was easily 2-3 mph faster in places where i was noting my speeds for comparitive purposes. The biggest thing was; I am able to climb with a higher gear and less perceived effort. While this trial was definitely not super scientific, it has given me reason to pause and study the situation a little more. I was ready to pull the trigger, too...

Mark

 

[Gromit]

Mark B wrote: I have pulled in my horns on short cranks. I had a "hold on a minute" moment yesterday when I did a trial with my longer cranks. Same bike, same route, the only diffrence was the different cranks. I was easily 2-3 mph faster in places where i was noting my speeds for comparitive purposes. The biggest thing was; I am able to climb with a higher gear and less perceived effort. While this trial was definitely not super scientific, it has given me reason to pause and study the situation a little more. I was ready to pull the trigger, too...

Mark

Mark
How tall are you? Maybe the length of your legs is a factor? Longer legs. Less advantage in using shorter cranks?

 

[Doug Burton]

Although I'm doing some short-crank development on a Sofrider right now, my experiences have mirrored Mark's.

I had 155mm cranks on my rotator Tiger. My next bike was a Vision R40, with 172.5mm cranks, and it was night and day for me. My legs just felt "freed-up" to apply more power. With the 155's I was pedalling 90 - 110 rpm all the time - moving a lot of meat around, but not going very fast.

That said, the Sofrider I shipped out to CA last week is very pleasant with a 155 triple, 48-36-24 with 11-32 cassette.

That's partly why I shipped it to someone else to get the performance evaluated.

I'll keep you posted.

 

[Gromit]

Maybe the Cruzbike's MBB is also a factor to take into account?
Though one of the supposed benefits of the shorter cranks is a reduction in strain on the knees. One for Dr. Jim?

 

[Mark B]

Gromit wrote:

Mark B wrote: I have pulled in my horns on short cranks. I had a "hold on a minute" moment yesterday when I did a trial with my longer cranks. Same bike, same route, the only diffrence was the different cranks. I was easily 2-3 mph faster in places where i was noting my speeds for comparitive purposes. The biggest thing was; I am able to climb with a higher gear and less perceived effort. While this trial was definitely not super scientific, it has given me reason to pause and study the situation a little more. I was ready to pull the trigger, too...

Mark

Mark
How tall are you? Maybe the length of your legs is a factor? Longer legs. Less advantage in using shorter cranks?

I'm 6' with fairly long legs.

I really like the way the short cranks wind up. By that, I mean that the short cranks get you moving really quickly. I just think you lose a step or two in top end and in power. For me, the loss of power seems to be a bigger loss than the quick bursts of speed, if that makes any sense.

I'm not making any rash decisions, just yet. It does bear more study for me, though.

Mark

 

[John Tolhurst]

the concept runs like this:
if you use a saddle, then you rotate your hips a little, so the foot doesn't actually do the full circle relative to the hip socket

on a cruzbike, you can still enjoy some hip action :geek:

but your previous conditioning plays a big part

Mark, I think you might go down about 10 mm and find it smoother, better, faster

 

[JonB]

johntolhurst wrote: the concept runs like this:
if you use a saddle, then you rotate your hips a little, so the foot doesn't actually do the full circle relative to the hip socket

on a cruzbike, you can still enjoy some hip action :geek:

Does this apply to both the freerider and the Silvio, because the seat pan was lifted alot more on Ole's El-Silvio than on my Freerider

 

[Mark B]

johntolhurst wrote: the concept runs like this:
if you use a saddle, then you rotate your hips a little, so the foot doesn't actually do the full circle relative to the hip socket

on a cruzbike, you can still enjoy some hip action :geek:

but your previous conditioning plays a big part

Mark, I think you might go down about 10 mm and find it smoother, better, faster

That's my thought, too; go for a happy medium. Maybe 155's go beyond the point of diminishing returns, for me.

Mark

 

[Doug Burton]

Mark B wrote:

johntolhurst wrote: the concept runs like this:
if you use a saddle, then you rotate your hips a little, so the foot doesn't actually do the full circle relative to the hip socket

on a cruzbike, you can still enjoy some hip action :geek:

but your previous conditioning plays a big part

Mark, I think you might go down about 10 mm and find it smoother, better, faster

That's my thought, too; go for a happy medium. Maybe 155's go beyond the point of diminishing returns, for me.

Mark

The sweetest MS150 I ever rode was on my red bike with a 165mm Tiagra Triple. On my Silvio ride I got pulled off the course by the SAG because of heat prostration...

Hey, it wasn't the bike's fault...

 

[Mark B]

Hardtailcruzer wrote: The sweetest MS150 I ever rode was on my red bike with a 165mm Tiagra Triple.

Im keeping my eyes open. I found a Sora crankset on e-bay, but I know those have steel rings.

Mark

 

[defjack]

The short cranks are working for me. I havnt noticed any speed loss and my knees feel much better during a ride. Jack

 

[Mark B]

defjack wrote: The short cranks are working for me. I havnt noticed any speed loss and my knees feel much better during a ride. Jack

Cool! I noticed a pretty dramatic drop-off, but my legs are longer than yours... I'd guess 155's are just titch too short. I'm going to try 165s and see how those go.

Mark