Q factor: Shimano vs Suntour? vs M-ighty?

bigflangesmallsprocket

I did post this subject in the mtb section, as the kit is mostly mtb based, but it seems mtb'ers care not a jot for Q factors. So I'm posting here. Roadies probably arent interested in Q factors for mtb kit!

I've just purchased a Carrera Subway Ltd Edition and even though it's the mens small (18"), it still has 175 cranks! Well I'm a skinny built shortarse so I'm not keen on the Q factor nor the length. I'm looking at budget 170mm replacements:

http://www.halfords.com/webapp/wcs/stor ... yId_165545

http://www.halfords.com/webapp/wcs/stor ... yId_165545

The above look look interesting as they look as if the arms don't flare out so much, so a smaller 'q' factor? Plus of course, both are sold by Halfords as replacements so should not void my warranty.

I've also seen these in 170's:

http://cgi.ebay.co.uk/SR-Suntour-XCM-V2 ... 335f6fe7ed

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEWAX:IT

which aren't sold by Halfords, but do look interesting nevertheless. I'd be very grateful if anyone could compare Q factors for me!

Blue Meanie

I'd be wary of how crank arms look, it is really best to trial-fit them.
Also, you can squeeze 5mm from the position of your cleats.

There should be a K-Factor for how far your knees stick out. I do enjoy lampooning newbies on road bikes whose knees stick out further than their elbows

bigflangesmallsprocket

I did pop into Halfords today to have a look. Youre right, it's pretty hard to compare chainsets just from a visual, especially if you don't know what bottom bracket is fitted on the example.

For this bike I don't intend to use pedals that require cleats: I have slightly odd leg lengths and I've had to add a spacer under one cleat for use with my road bike. This means that when I'm walking I do a pretty good impersonation of having a noisy limp and it's not an especially comfortable experience.

Reading up some, and looking at my own bike, theres a tendency toward wider than necessary chainlines on mtb sytle bikes, so simply getting a bottom bracket to reduce the chainline back down could be a good and relatively cheap start, though I still want shorter cranks really.

nicklouse

as it is Square taper cranks a change of BB axle length would be the easiest option, but watch out for rings fouling on the chain stays.

As mentioned by others before.