EuroYank
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Thanks for the feedback FnF! Sounds like your new bike is working well and still providing opportunities to tinker. New 50T ring looks good. Whole darned bike looks great. I would kill to have a chain that clean.I hear ya and just installed a 50T 130BCD WolfTooth on Gumbo Dacious - closing on 100miles riding - before this storm (It snowed in San Diego Campo area right on the US/ Mexico border. Ugh).
For the Lm'td I found these Decas Ring Gears are inexpensive ($15) and last well.
It should list the sizing on your present ring. If not: Here's a link on how to measure the ring.
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I so concur. It's an economical, simple improvement. I'd dare say for any terrain the Lm'td is meant to run.
A 48T, while it won't make the bike faster, improves the Lm'td where you have to pedal less and the gearing is less tilted towards vertical terrain.
Rear hub's are RPM limited. From that point onward torque drags, not pushes.
Even old as dirt, this stuff fascinates me !!!
This link shows the relative Power Curves of rear hub drives. Notice from '0' down you see negative torque values?
0 = 30.7mph (Zero Efficiency) and 0nm. At 32.31mph, you're dragging against '10nm's' (plus the weight of the machine).
Set the display controller value to 26" wheels, whatever and the true rpm of the rear wheel will 'produce' the same result.
If you can't increase the wheel size, game over.
Mid drive being different - the ring gear is (rpm limited) actually driving the rear wheel via a chain - a larger gear = more distance of chain moved per revolution.
Took me a bit to wrap my stubborn head around all this and I figured 'mid-drive are the way to go !!!'
Well sort of. Go to the LBS. They eat drivetrains.
If you shift, just getting on the cog when that power kicks in is pretty destructive.
Pedal one-quarter turn of the ring and BANG, big torque - right when the 11T on the cassette is just engaging the chain on it's third tooth and a 12T only has three teeth engaged.
You follow me?
Shifting technique is 'Pause, shift. Pedal one-eighth turn, pause then pedal (now fully engaged on the cog) and maybe cassette, ring and chain lasts 1000miles, not less than 300.
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Hub drives are more economical, require less maintenance and have a built in safety factor: if drivetrain fails, the throttle will get you home.
Yes, a 48t will be slightly taller. I advise against offsetting, changing the chain-line. Everything I read says it causes excessive wear and (often/ sooner or later) causes shifting problems. I've seen the effect in other applications.
A steel chain with a new (crooked) angle of contact at the interface of the gears; chewing up the alloy ring/ increasing chain wear on steel cogs - will seek to fit by abrading into that groove.
If the chain wears, next up is the derailleur. All these parts are relatively inexpensive, but IMO: still an expensive compromise to use a larger ring that won't make the machine any faster (ie: Bang for the buck).
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I'm sure you're studying up - and BTW, Big Congrats on repairing that MXUS!
Nothing on that machine is even slightly beyond your ability.
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I couldn't discern if a 48T would fit the Lm'td until I tried it.
Contrary to online instructions, I didn't have to increase the chain length with the Lm'td (44T to 48T, or with Gumbo (46T to 50T).
My only problem was finding a bash plate/ chain-ring guard for the 48T. You won't have that.
Here's the 50T on Gumbo
View attachment 142382
View attachment 142383
It made a 9% Difference.
Next up (1000miles down the road), installing a two-link longer chain and a 52T Ring.
View attachment 142384
That's the 46T. I've got the space.
With you, I'm a Flatlander with miles of flat Coast to cruise.
Fn'F
I’m still sold on this simple cadence rear hub bomber of an ebike. Takes more than a “thermal incident” to dampen my enthusiasm. Now that I’ve dialed in my PAS, it’s a fast flat-landers dream bike.
I’m glad you advised against a chain line offset, as I had considered it. Interestingly, the R1U chainring FAQ suggests requesting a 45T ring when ordering the LMT’D. I’m not sure why; 1 tooth seems insignificant on a sprocket that big.
I also want to thank you for reminding me; the bike is fine just the way it is. In fact, I think I should be finding ways to use the low gears instead of trying to make the front ring 4 friggin teeth bigger. Maybe I’ll take up trials riding. Onward and upward…