mark_243245

Hi, I have a 2006 Gary Fisher Hoo Koo e Koo. 26" MTB. Used as a commuter with 32mm Continental Sport Contact tyres.

I recently changed the rear wheel on this bike as the original one was out of true, while I get the original one trued.
Just a cheapish new 26" wheel (~ $180AUD) from a local distributor / wheel maker with Alex DM-18 rims, Joytech hub and 8/9/10 speed Shimano HG compatible freehub, to put on this bike.

The bike has a 3x9 gear setup as original.

But I think after changing the wheel to the new one I bought, the rear shifting isn't as supple. Upshifting (towards harder gear) is quite metallic sounding (twang) and a bit jarring on the legs, especially when shifting from biggest to sprockets to the next smallest one. The upshifting up the smaller cogs of the rear cassette is a bit more supple and smooth.

Would this likely be a problem with the freehub that came with the new wheel's hub assembly (likely to be a cheapish one like Joytech)?

I also bought a new cassette (11-34T HG400) and a new chain (HG53). I also even bought a new 9 speed rear derailleur (Shimano Alivio RD-M3100-SGS). Strangely the same experience in upshifting problem persists throughout these new components being installed, the same shifting quality as with the old derailleur (Deore XT M751-SGS from 2006), old stock SRAM chain and old cassette.

I have tried changing the b-spline but cannot adjust it to be very good or much better.

Does anyone know the main causes of (during upshifting and not downshifting) the cogs losing transmission and causing the rider's legs to jump forward which is jarring (hurting) your legs?

Apart from this upshifting poor quality experience of riding the bike, the rear derailleur is in perfect adjustment as far as cable tension goes. Every shift is not too slow and goes into the right gear every time within 250-500ms.

It seems to me that this isn't how a Hyperglide cassette should normally work, it should be better usually.
I have another new hybrid bike with Altus derailleur and 7 speed HG cassette, and it shifts much more comfortably.

Next step I have for this bike is to try to adjust the derailleur hanger, once the tool I bought has gotten posted to me. See if that improves the upshifting quality.

Thanks.

FBinNY 

Assuming you transferred thr cassette, we can rule that out. Likewise, I'd discount the hub or freehub, since they don't usually factor into a shifting.

However, hubs are not all precisely matched. (in engineering or manufacturing terms, "qualified") That means that the cassette is probably not in exactly the same place with respect to the RD, causing the trim and shifting to be off slightly. Thats why it's SOP to check trim and limits when changing wheels, and if you haven't done so, do it now.

Lastly, consider that wheels vary in how they resonate, so it might just be that.

Iride01 

Some of what you describe sounds just like poor shifting performance because you are shifting at too low of a RPM/cadence and are having to use too much power to the pedals to keep moving. So maybe just shifting before your cadence gets too slow might help.

If the sprockets are in a different position due to the wheel changes, the clang might be that the side plates of the chain are getting hung on the top of the teeth as the wheel turns and then when you get to the strongest part of your pedal stroke the rollers fall into place giving you slack that is instantly taken up buy the crank. Did you turn the barrel adjuster to see if that puts the RD in a better position to complete its shifts faster?

Kimmo

Was there a new cassette on the new wheel, that you're using with the old chain?

mark_243245

No I used the new chain with the new cassette and the old chain with both the old (obviously) and new cassette (to test) (all with the new wheel).

The old wheel is out of true so I can't test ride it very safely.

The current setup that I'm talking about there is the new chain and new cassette together (on the new wheel).

Funny thing is, same sort of problem with the old cassette on the new wheel (the cassette, I ultrasonically cleaned and put on the new wheel after cleaning to start with before going out of my way and buying a new cassette to put on instead, in case the old cassette had too worn out teeth).


BTW prior to buying the new wheel, I had problems with the old M751-SGS RD with the old cassette and old wheel downshifting (left, towards the bigger cogs) (perhaps having the barrel adjuster too much turned clockwise (putting the RD more towards the smaller cogs) due to lack of cable tension from the RD spring pulling the RD right when upshifting). But then I ultrasonically cleaned everything (RD, cassette and chain) and lubed up my shift cable housing and put a new shift cable lubed up with Muc-Off wet lube and that problem went away (albeit only tested with the new wheel, old derailleur, old cassette and old chain). Downshifting into the correct gear (cassette cog) worked every time, once I had done that shift cable housing lube up (with the new wheel). I can't test the old wheel because I took apart the hub cones and reassembled the hub bearings but then found the wheel was too out of true to actually ride; something must have put the wheel out of true before in the last 10 years. Could have been sticks on the trail or street getting into the spokes, or something else banged the wheel.

But the new problem I got with this new setup and new wheel arose where the pedals slip when upshifting, jarring my legs. (Which it wasn't really happening too much before I took the bike all apart at which time I instead had the problem with downshifting missing a cog on the cassette as per the above paragraph).

mark_243245

Yes, this is exactly what is happening. Here is a picture of the chain and cassette just the moment before the crank takes up slack resulting in the pedals slipping when riding. This photo was taken on a bike stand, not during riding. I held the rear wheel back counter-clockwise with my hand whilst turning the crank clockwise, creating the normal riding condition of wheel friction with the road. As soon as the crank is turned any further, the slack is there like you said, just as the rest of the chain slips onto the smaller cog I'm upshifting to. As soon as the chain slips onto the smaller cog, this slack is instantly taken up by the crank resulting in the pedals slipping/jarring when riding/pedaling with your leg.




I tried turning the barrel adjuster right with the downshifting still working OK. The slack was lessened a bit but there is still a bit of slack the crank has to take up.
Is this normally the way a Shimano hyperglide HG400 cassette works?

Actually the bikeforums.net website isn't letting me upload the photo as I haven't got 10 posts yet.

mark_243245

Test post (2 more needed to upload the photo on bikeforums.net rules).

mark_243245

Test post (1 more needed to upload the photo on bikeforums.net rules).

Iride01 

What make and model shift lever or STI are you using? Although I'm not sure that in 9 speed applications there is any difference between mountain or road bike components. If by some odd chance you have a 11 speed road shifter or a 10 speed Tiagra 4700, that would be a issue shifting on that 9 speed cassette... for several reasons

mark_243245

Both left and right shifters are the stock ones on this Gary Fisher Hoo Koo e Koo bike from 2006. Shimano Deore SL-M510 left and right. They are quite old now and the right shifter was stuck a couple of months back from years of shed storage with the bike. I fixed that by spraying WD-40 into the shifter cable hole. Then later I ultrasonicaly cleaned the right shifter to try to improve its performance. It seems OK to use now in terms of pressing the levers, etc.

I have another bike (new cheap $400 commuter bike) with a 7 speed Shimano drivetrain (HG cassette, Altus derailleur) and, whilst it looks similar to the human eye on the bike stand with the chain as in the above photo, in actual practice whilst riding, there is very little pedal jarring your legs from the upshift on this bike. Which leads me to believe there is something that could improve the problematic Gary Fisher HKEK bike.

hokiefyd 

In my experience, the physical thing happening here is the chain links land on the teeth of the next smallest sprocket, rather than in the valleys between the teeth, and pedal pressure will cause the chain to ride forward by half a tooth and "clunk" home into place. You'd think this would happen pretty seamlessly during riding, but it often does not, and it's something you can very much feel.

Does this happen with every gear change, or just between two or three sprockets? I have two HG400 11-36 cassettes installed on two different bikes, and the shift from the 3rd largest sprocket to the fourth largest sprocket (from the 26T to the 23T as I recall) would be a clunk shift about 90% of the time. Whether I was riding the bike or pedaling it on a bike stand...that shift was just never very smooth. Other shifts were -- I could upshift to a smaller sprocket, and the chain would fall down and just lap into place. But this one particular shift was just never very clean. I attributed it to some intangible combination of factors, but possibly including sprocket design/matching on the cassette -- 26T and 23T are somewhat uncommon sprockets and maybe they just aren't very well matched to each other. That HG400 cassette (both of them, really) always shifted that way, regardless of rear derailleur or even which bike it was on.