Why MTBers don't seem to care about q-factor?
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As someone who has always appreciated reasonably narrow q-factor cranks, I have to say I struggle with current MTB trends with ever widening q-factor stances. Why is it that MTBers don't seem to care about this?
Shimano XT is a laughable 172mm or 178mm in boost form. I haven't checked SRAM XX1 recently but I gather it has increased from the good ol days of 156mm?
Old XTR was 158mm which was okay, although M9100 is now 162mm I think.
Shimano XT is a laughable 172mm or 178mm in boost form. I haven't checked SRAM XX1 recently but I gather it has increased from the good ol days of 156mm?
Old XTR was 158mm which was okay, although M9100 is now 162mm I think.
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Right, my spark is optimized for 55mm chainline, that's additional 3mm on each side. Luckily my XTR pedals, are with shorter axle... but still
SW SL8 RTP 56cm @ 9270 / CLX II / CS OSPW / CEMA BB
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S Epic 8 L @ XX T-Type / Berg Ratheberg 30 / Quarq / Fox Transfer SL 100mm / 3p
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Because the section of the market that is interested in narrow Q-Factor cranks is steadily becoming smaller and less fashionable.
It's all about the techie riding now, not the long hours in the saddle knocking out tempo.
Big tyres, complex suspension designs, all need more space.
FWIW i used to run the old polished XT cranks (m737) on a road bottom bracket (no lockrings) with almost a track sized axle (103 IIRC) to get my q-factor down. There was about 1.5mm between the inner face of the crank and the bottom bracket cup.
But then, the races i was doing then were 45-60 minutes per lap with at least 50% fire road, so tapping out at race pace was essential, sometimes for 10+ minutes at a time. On drier, flatter courses, you'd see average race speeds around or over 20kph.
The last mtb race i did, my average speed was about 12kph and the longest, uninterrupted bit of pedalling without either a sprint up to pace, tech feature, tight corner, rock/root feature, fast tech descent or a stop and hop was about 500m. Not sure if the pit straights or the arena straight was longer.
I don't suffer with the wider q-factor on the MTB. (a fat bike might be taking it too far though!)
On the road, wider q-factor cranks still cause me issues with my hips and knees.
It's all about the techie riding now, not the long hours in the saddle knocking out tempo.
Big tyres, complex suspension designs, all need more space.
FWIW i used to run the old polished XT cranks (m737) on a road bottom bracket (no lockrings) with almost a track sized axle (103 IIRC) to get my q-factor down. There was about 1.5mm between the inner face of the crank and the bottom bracket cup.
But then, the races i was doing then were 45-60 minutes per lap with at least 50% fire road, so tapping out at race pace was essential, sometimes for 10+ minutes at a time. On drier, flatter courses, you'd see average race speeds around or over 20kph.
The last mtb race i did, my average speed was about 12kph and the longest, uninterrupted bit of pedalling without either a sprint up to pace, tech feature, tight corner, rock/root feature, fast tech descent or a stop and hop was about 500m. Not sure if the pit straights or the arena straight was longer.
I don't suffer with the wider q-factor on the MTB. (a fat bike might be taking it too far though!)
On the road, wider q-factor cranks still cause me issues with my hips and knees.
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Because we cannot. Nobody will listen. As mentioned market is all about more everything, bigger this, wider that..
If you want narrow q-factor mtbs and scream about it only neighboors dog will hear you.
If you want narrow q-factor mtbs and scream about it only neighboors dog will hear you.
Indeed...kaptanpedal wrote: ↑Sat Apr 23, 2022 8:09 pmBecause we cannot. Nobody will listen. As mentioned market is all about more everything, bigger this, wider that..
If you want narrow q-factor mtbs and scream about it only neighboors dog will hear you.
I get that Shimano and others need to offer wider stance options because of the growing axle and chainline dimensions, and generally more chunky bottom bracket and chainstay zones. It doesn't make sense to make cranks which don't clear the average modern frame.
Having said that, I reckon frame manufacturers could improve the situation by profiling their chainstays better at the inner crank zone.
I tried to make my pedal stance narrow. But then my heel scrape the rear triangle. It's the rear triangle vertical brace between seatstay and chainstay that overlap to the side of seat tube. If you struggle to imagine what part this is, just search for picture of vpp suspension. So, I can't even put cleats all the way out (to make stance narrow) on short axle XTR pedal with XX1 crank.
My preference is to minimize Q factor on all my bikes.
One of my hardtails is an older SC Highball with 144mm Q as a result of a swapped SRAM crank spindle.
The AX-Lightness XC frame has BB92, so the narrowest crank that fits is 148mm Q.
It is certainly possible to make frames to fit 2.4 tires and still have a very narrow Q.
One of my hardtails is an older SC Highball with 144mm Q as a result of a swapped SRAM crank spindle.
The AX-Lightness XC frame has BB92, so the narrowest crank that fits is 148mm Q.
It is certainly possible to make frames to fit 2.4 tires and still have a very narrow Q.
I think a wide Q factor helps stability and control of mtb.... just guessing. Maybe it's like trying to do Judo with your feet together!
But I prefer narrow.
Dont forget you can get shorter pedal axles to reduce Q. I run egg beaters with after market ti spindles of shorter lengths.
But I prefer narrow.
Dont forget you can get shorter pedal axles to reduce Q. I run egg beaters with after market ti spindles of shorter lengths.
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