Poor frame design?

[Phileas]

I know the answer to the question really but I'm just after a second opinion.

I recently bought a low-cost frame from an established online manufacturer. Having built it into a commuting bike, I'm finding that my left heel quite often rubs the frame where it bulges at the disc caliper mount.

The frame I bought is the size recommended for my height (5' 11") and my feet are size 11. The shoes I wear are Shimano SPD. Admittedly they flair out a little on the heel but it seems to me my foot should comfortably miss the frame.

[Cyril Haearn]

Maybe you should be ankling a bit more, if you learn it soon becomes automatic

[CJ]

I agree with you: poor design. If your shoe heel doesn't rub the crank (which it would if your pedalling were excessively toe-out), there's no good reason why it should rub the chainstay. And cycling shoes commonly come in sizes up to UK12 (48), so neither are your feet excessively long.

The problem is that frame designers often do not make the chainstays any longer at all, on frames for larger people. That's poor design, but poor design is regrettably commonplace. It comes about because bigger people expect their frames to be just as light and just as short wheelbase, as those that are correctly proportioned for average-sized people.

[CJ]

Maybe you should be ankling a bit more, if you learn it soon becomes automatic

And if the fabled Emperor had been a man of taste, he would have appreciated how fine were his new clothes!

[Valbrona]

Other shoes/pedals might put your feet further out, so giving greater stance width, or Q Factor. An internet search might show which combos favour greater stance width. Some pedals also allow for the insertion of 'pedal washers' on the threads, but be cautious about this because some pedals do not have enough threads.

[Phileas]

I'm using a Shimano Alfine crank which may be narrower than average.

I could probably do a few things to improve (perhaps even virtually eliminate) the problem but could I reject the frame as faulty or unfit for purpose?

[Brucey]

you could fit a pedal extender, e.g.

https://www.sjscycles.co.uk/pedals-cleats/20-jtek-qplus-pedal-extenders-916-inch/

or try different shoes....

-but otherwise it sounds as if you are in the poop.

IIRC your old frame was steel with a 135mm oln rear and a disc mount in the same place; aluminium tubes are usually a bit fatter but even so it is surprising that it has made enough difference to cause a clash like that.

cheers

[Phileas]

Thanks Brucey, I'll consider those.

[Tompsk]

Sounds poor to me. At the 'other end' how is the toe overlap with the front wheel? From memory this was seen as a safety issue but AFAIK the construction rules allow designers to get around this by assuming everone has a tiny shoe size, perhaps they do this at the back too? Not sure if construction rules apply to frame & fork sales.

The craze for shaving every gram and every penny off mean chain stays are often the same length or only a small difference for all frame sizes.

[531colin]

This problem will get more frequent.
Shimano's newer, more expensive compact double chainsets have a narrower "Q" factor than older designs......no doubt that's the frame designer's "fault" as well.

I'm using a Shimano Alfine crank which may be narrower than average......

Is it the same/similar to the chainset on the previous bike?

What should the designer do?
Short chainstays are on the "wish list" for most fashion-conscious buyers.....
So do you design something fashionable, which will sell, or something practical, which will work?

Is this mystery frame a fashion item or something which is supposed to be practical?

...........It comes about because bigger people expect their frames to be just as light and just as short wheelbase, as those that are correctly proportioned for average-sized people.

.....Quite.....if you want to sell quantity, you need to make what the man on the Clapham omnibus wants.....whether he knows what he needs or not.

[Phileas]

I bought the mystery frame because it was cheap and made of aluminium, certainly not for fashion reasons. I didn't really give geometry a thought - it's for commuting so I'm not on the bike for long enough to care. I just didn't expect my foot to rub as I've never experienced that before.

I dare say I can put up with it.

[fausto99]

In defence of the frame maker, I'm guessing that you pedal with your heels in. I do and I didn't realize it until I began to see slight wear marks on my cranks. So, unless you know and show the frame builder your habitual foot movements, how would he know how to design your chainstays?

[PH]

It seems to have been decided that the fault is the length of the chain stay, but it’s not a problem on the other side which makes me think it’s poor design of brake fitting.
I sometimes get heel rub on most bikes, I think I ride toe out when pushing hard. First thing is to protect the frame, you don’t want to rub the paint off, I use clear tape. If you feel you need to avoid it another option to those already suggested it a longer B.B. and chain ring spacers to maintain chain line (Assuming SS or IGH?) Or even run with a slightly imperfect one.

[willcee]

Something that I have found in the past year from a guy who has been calling with me for advice and assistance over many years and various machines during that period.. heel rub on d / s carbon stay ... not from he bought the machine but just after he and the club did a 400mile ride in 4 days for charity.. I looked after his previous steeds and they never had any issues with rub, he uses spd sl and I asked about the cleat alignment, funny enough he says felt that the right wasn't just as it should be.. problem solved.. cleat had lost a screw loosened one other bolt and we sorted it.. no more heel rub , so my advice check your cleats might just be your issue.. will

[Phileas]

The left stay is definitely wider than on my previous disc bike although this picture doesn't prove it: