Originally Posted by
mtbvfr
Hi Yuri,
Thanks for the detailed response.
I will pay attention to your thoughts about cadence at different gear ratios and see whether I'm my butt is moving forward under higher cadences or lower cadences. Current cassette is using 8 cogs (12-32) from a 9-speed cassette on a 7-speed hub. Chainrings are 20-34-46. Next step will be to use 9 cogs from a 10-speed casssette. There's a change of about 10 rpm between cogs which may be better managed when I can get around to swapping the 34t chainring for a 36t and then shift between the 2 outer chainrings in the opposite direction to shifts on the cassette to maintain optimum cadence. I like it between 90 - 95 mostly.
I use the tyres, you see, on both asphalt and gravel with allowances for lack of grip in the corners on the gravel.
Measurements were taken by Andrew Pruitt in Denver in 1994 but the solution he offered never worked for me. Changing to unequal and longer cranks back in 2009 helped rather significantly.
I just recently dropped the saddle about 2.5-3 mm and that actually improved things. I noticed I was spinning more easily and I was moving my butt back less often. I'm going to try dropping it another 2mm.
Understand about the injuries; wearing a shoulder brace for the right shoulder and elbow guards.
Will report back another day.
Keep the rubber side down, MTB.
yeah 10 rpm diff on gear changes is quite sizeable (if it were for 'road'), but still workable. I always had a problem on mtbs with wide cog ranges, where the rpm diff. was greater... in one gear you're 'pushing' too much, but dropping down one cog has one spinning out... and a front/back combo shift to get the right gear is a pain...
do you still slide forward as much, after dropping your seat? I'd be surprised if 'that' didn't improve (less forward sliding...) after lowering the seat.
Most riders I see on mtb are quite 'low', because of wanting lower COG for stability - hence my initial rec for raising a few mm. Given your optimum cadences you like, you're obviously not too 'low', otherwise spinning at those rpm would be more difficult...
It might be that the 'sliding' is just 'You', not wanting to drop to the next gear down, because you know your speed will suffer... LOL!
...also wearing a shoulder brace at the moment... dislocated my right shoulder again, 6 wks back - but I can still ride, if I keep the elbows tucked properly... LOL!
having a difficult time wrapping my head around what might be advisable at the current age...
lemme know what you come up with - it's an interesting situation, and worth learning a bit more about...
.... I think the varying crankarm lengths is a great solution for your leg diff. !
Did it take long to become accustomed to the different 'feel' from side to side, different foot/leg pedal stroke in any way?
Ride On
Yuri