Ideal chainstay length?
 

Just out of curiosity, what is the acceptable length of everyone on a "touring" bike for chainstay (measured along the frame, not a plumb dropping from the rear axle)?

I was working on my cheap build today, and it was nice out, so I loaded up the intended panniers and went out for a rice. Keeping in mind that the rack is not the intended rack, and the one I am planning on using sits higher and a little further back, I was heel striking occasionally. This got me thinking, and I measured it out exactly. The chainstay on my Miyata 610, which never had a heel strike issue and has 5mm longer cranks, is 438mm, and the MTB having issues was 439mm. Effectively the same. Is this truly long enough on a touring bike?

For reference, I am planning on using a similar rack to the Miyata, which sits 8cm higher and 1cm further rear than the cheap commuter rack on the MTB, and I've got midget 8.5 feet.

440mm is often considered the minimum and many touring bikes are 450 and longer. But things that affect heal strike are as you noted, the rack, the pannier size and shape, shoe size, where your shoe contacts the pedal and even crank arm length (165mm has a full centimeter advantage vs. 175 mm) and finally your individual pedal stroke-how toe down are you when lifting the pedal or ar you more flat footed. I'm a 44 shoe size (9-9.5) but regularly tour on bikes with 425mm chainstays without heel strike and my cranks are always 175mm.

Touring specific bikes have about 460 mm chainstays for a 58 cm frame. The bike I use a lot is a Bianchi Volpe, a CX bike, 57 mm frame. It has 416 mm chainstays, about 1.75" shorter than the touring specific bikes. I use Ortlieb Back Roller Classics on a Tubus cargo rack. I have size 10 feet, and just barely clear the the panniers on the 416 mm chainstays. I'm not sure why you are having heel strike issues; your bike's chainstays are only about 3/4" shorter than most touring bikes.

Those 439mm chainstays should work for most folks. My chainstays range from 450-470mm and my shoes are size 51. The only heel-strike issue I have is with the shortest chainstays if I choose to use my largest panniers and wear running shoes with a big padded heel. If you're wearing normal cycling shoes and don't have clown feet like me, you shouldn't have any problems unless your bags have a particularly rounded shape.

I have bikes with 440mm and 450mm. Size 14 shoes. 170mm cranks. No strike, but I set my bags towards the back on the rack's bars.

@jefnvk. I used my mountain bike with it's 42 cm chain stays without heel strike. Other considerations are 9 1/2 shoe size and a 175 mm crank arm. Most expedition level touring bikes look to have something around 44 cm long chain stays. My Cannondales' have 18"/~45.7 cm long chain stays.

The mountain bike only has one set of eyelets available, but I don't use very large panniers (I don't remember the size.) which are about the size of those used on a low rider front rack.

Pannier size, length of the rack's supporting strut, which (if optional) eyelets are used, position of those eyelets, and chain stay length all contribute a portion to cause or solve the problem.

Brad

Cool, thanks for the measurements! Good to see numbers of what people are actually using, more practical IMO than looking at catalogs of new bikes.

The rack I was using is not really meant for loading bags on, just one of those cheap ones meant for strapping things on top of. Bag sits too low, it was nearly on top of the derailleur and the cable was in the way of it mounting, I wouldn't want it on an actual tour like that. The ones I am looking at all move the bag up and back. I don't foresee it being an issue, was more just curious as to other real-life measurements. Even with it sitting like that, it wasn't generally an issue, but I did feel a tap every now and then.

http://i1376.photobucket.com/albums/...pskpojwcfn.jpg
(yes, panniers overstuffed, just shoved blankets in to fill volume)

http://i1376.photobucket.com/albums/...psnovr79wr.jpg
The current rack

Chainstay length can have other issues, like handling characteristics.

One of my touring bikes is 450mm, the other is 466mm. I dug out the sales brochures to look it up (it is electronic on my hard drive, only took a minute to look up). What surprised me was that different sizes of my touring bikes had different chainstay lengths. I did not realize that Thorn (brand of both of my touring bikes) changed the chainstay length for different frame sizes. I think most companies have one chainstay length for all of their bikes within a model. I just looked it up, LHT is 460mm on all sizes.

Regarding heel strike, I always try to use the pannier adjustments (Ortlieb panniers have adjustable hooks) to put my panniers just slightly behind my heels so I just barely avoid heel strike. Any further back and you start risking your bike getting a case of tail wagging the dog syndrome.

This is my bike with the 416 mm chainstays.http://i783.photobucket.com/albums/y...5/DSC00749.jpg

This is the same setup on a bike with 460 mm chainstays.
http://i783.photobucket.com/albums/y...l/IMG_2467.jpg

There is a slight difference in rear pannier position in relation to the rear wheel axle , but not much.

Hmm. It seems to me that you would want to vary the length for different sized bikes, to keep everything proportional. Then again, I'm no bike builder!

One advantage of a longer chain stay is that it is easier to mount the bag near the center of the rear wheel which helps improve the handling. But this is not a big deal in my experience and as others have pointed out, the rack and the bags you use make a big difference.

Yep, looking at it in general, your bags are mostly behind the rear axle, both look like they only have 1/4-1/3 of the bag in front of the axle. Mine were centered directly over it, with that rack on the MTB. Now that I look at old tour pics, my Miyata had it situated like that too (not as far forward as I tossed it on last night for comparison purposes).

Good to hear confirmation of the rack moving the bags around to fit is seemingly common, especially on bikes with much shorter chainstays.

You know if you were to lengthen those struts which attach near the seat tube, you could level that rack out and provide probably another 1cm in clearance, cheap fix and probably worth a try.

I thought about it before I left yesterday, but I'd have to make/buy new ones, as those are out as far as they can go. If I'm going through that effort, I am just going to buy a more suitable rack, with more baking between the bag and the pannier too. I mostly liked the Axiom Journey that was on my Miyata, minus the adjustable legs, the non-adjustable version is less than $25 on ebay.

https://images-na.ssl-images-amazon....1yWmOnLGjL.jpg

That axiom is what I'm presently using and it has held up well over the past few years.

Fully concur.

But most bike manufacturers cut a lot of corners if they can save a few bucks. And if standardizing chainstay length on all sizes of a model will cut a few bucks they do it. Same with tubing diameter and tubing gauges, most manufacturers will use the same tubing on all sizes within a model, that way the 250 pound big guy has a wet noodle for a frame while a small framed woman has a really stiff frame.

I took another look at the sales brochures from when I bought my two Thorns. On my Sherpa they used two different tubing sets and four different chainstay lengths for different sizes. On my Nomad they had two different tubing sets, but they actually overlapped for two sizes so for those two sizes you could buy the lighter weight tubing or the heavier tubing. My size was one of the two where they overlapped, so I could buy a frame with a capacity of 45kg without rider weight or 62kg capacity. Both of those weight ratings far exceed any load that I will ever want to carry, but I bought the heavier weight tubing to get a stronger bike. For the other sizes, they only had one choice of tubing, lighter for the smaller frames and heavier for the bigger frames. And the Nomad had five different chainstay lengths for their different sizes.

I am sure that there are other manufacturers that also use different tubing on different sizes for off the shelf frames but I really have no idea who they would be. But I am sure you are looking at the more expensive manufacturers for that.

I was just curious, so I measured the chainstays on my wife's 47 cm frame. Even her small frame has 455 mm chainstays. I think it more a factor of providing room for panniers regardless of frame size, not trying to cut corners. Panniers take up the same amount of room on the rear triangle on any size frame.

It was custom built by a reputable builder, and it handles really well. She only carries rear pannier, and a small bar bag. Her usual load probably does not go over 35 lb. I've ridden behind her downhill at 42 mph, and she would be pulling away of me.

This is her touring setup, and and the bike is rock solid, and she handles that bike extremely well.
http://i783.photobucket.com/albums/y.../Co-Motion.jpg

out of the tube set box the tapered chainstay tube is only so long..

when I made my light touring frame, I used the whole length .

to get a solid brazed joint in the cast steel BB shell ..

a little was cut off as I cleaned up the threads inside the BB

this bike frame from the mid 70's is still being ridden occasionally..









....

Which touring bike has the longest chainstay? is it the LHT at 460mm?

I have issues with heel strikes even on my trek 520 which had a chainstay of 450mm. I have big feet and I prefer to have the tip of my foot on the pedals.

Its gotten to the point where if I havent hit my pannier in a few mins I usually look back to see if my panniers have fallen off

Yes, the LHT has 460 mm chainstays.

Even on our daughter's 42 cm LHT, the rack fits quite a bit higher than the rear wheel. The rear rack is a Bontrager "S", made especially for road frames smaller than 50 cm or Mountain frames 18" and smaller. This might be a good option if you are riding a smaller frame mountain bike.

http://i783.photobucket.com/albums/y...ed_Reduced.jpg

The rack lets the panniers ride higher and is still very solid.
http://i783.photobucket.com/albums/y...ed_reduced.jpg

The longer the better! ;)

http://www.ravingbikefiend.com/bikep...ldtourist1.JPG

Yep, this one is a 16". I actually looked at a Bontrager last night when I was at a LBS, they seemed solid and fairly reasonably priced. Only had disc models in stock, though.

Rivendell has been developing extra-long chainstay bikes lately, for touring and commuting. For example, their Appaloosa bike has between 51.5 and 53.5 cm chainstays, depending on the size. https://www.rivbike.com/products/appaloosa-framesets

Their Cheviut step-through has 54 cm chainstays in the largest size.
https://www.rivbike.com/collections/...oducts/cheviot

And their Clem Smith "budget" model has 56 cm chainstays in the largest size!
https://www.rivbike.com/pages/geometry

They've even tweaked the geometry of their flagship touring bike, the Atlantis, and lengthened the chainstays to 49 cm in the largest size.

They advise that you'll need to buy a tandem length chain (or two standard chains). I haven't ridden their new designs; my Riv is an early Road Standard model with traditional road bike geometry. But the folks who have ridden these bikes love the comfortable ride. Probably a bear to handle on singletrack, but excellent for road touring.

Also, most of their new designs offer 26", 27.5" (650b) or 29" (700c) wheels, depending on frame size. Tire clearance stays constant regardless of wheel diameter across each model.

They make expensive bikes with gorgeous paint and lugwork (and sometimes dumb names). They know how to build an excellent touring bike (as do many others).