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Premium Member
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Discussion Starter · #1 ·
Ok heres the deal I bought a 21 trek rail 9.8 xt and tore it apart in my kitchen and rebuilt it with all XTR 10-51t cassette XTR derailleur shifter and 4 piston XTR brakes. I also pulled the Bontrager pro 30 ally rims with the
Bontrager alloy, sealed bearing, alloy, 6-bolt, Rapid Drive 108, Shimano MicroSpline freehub, Boost148, 12mm thru axle rear hub
And replaced the wheels with
Raceface next 31s with the RaceFace Vault J-Bend 424 Rear Hub - 12 x 148mm, 6-Bolt, XD, Black, 32
But somehow the bike seemed snappier when it had stock wheels, Is this possible from the Hubs on the Bontrager 150 rims?? Im really asking, because Im no expert but I at least WANT TO know whats up.
Thanks
 

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Sneaker man
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3,464 Posts
Ok heres the deal I bought a 21 trek rail 9.8 xt and tore it apart in my kitchen and rebuilt it with all XTR 10-51t cassette XTR derailleur shifter and 4 piston XTR brakes. I also pulled the Bontrager pro 30 ally rims with the
Bontrager alloy, sealed bearing, alloy, 6-bolt, Rapid Drive 108, Shimano MicroSpline freehub, Boost148, 12mm thru axle rear hub
And replaced the wheels with
Raceface next 31s with the RaceFace Vault J-Bend 424 Rear Hub - 12 x 148mm, 6-Bolt, XD, Black, 32
But somehow the bike seemed snappier when it had stock wheels, Is this possible from the Hubs on the Bontrager 150 rims?? Im really asking, because Im no expert but I at least WANT TO know whats up.
Thanks
Just looking at what you had in bold, it looks like the raceface is XD driver, how did you get the XTR cassette on there?
But anyway it looks like (from my quick during lunch break search) the raceface are 1765 grams and the bontis 1608g... put the bonti's back on and sell the raceface
 

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Premium Member
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Discussion Starter · #4 ·
Things that may have an effect due to rotational weight:
1. Tire weight
2. Wheel weight
3. Rim weight
4. Allow nipples vs brass

If any of these is heavier in the second build, it could have a negative on "snappiness."
the bikes 3.5lbs lighter now
 

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Premium Member
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Discussion Starter · #5 ·
Just looking at what you had in bold, it looks like the raceface is XD driver, how did you get the XTR cassette on there?
But anyway it looks like (from my quick during lunch break search) the raceface are 1765 grams and the bontis 1608g... put the bonti's back on and sell the raceface
yea actually the bontrager set weighs almost 250 grams more. And the entire bike is now 3.4 lbs lighter thn when it was a bone stock trek rail 9.8XT
 

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Sneaker man
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Ah OK, liek i said, looking on my lunch break (well mostly in my lunch break!) so quick search, I pulled up the pro version and the comp version is as you say much heavier...
I guess put the bonti's back on and see if that changes anything
 

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Self Appointed Judge&Jury
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Maybe it’s the hub engagement pawls between the two hubs that is making the difference.
 

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Im really asking, because Im no expert but I at least WANT TO know whats up.
The problem is failed expectation. You changed stuff around, with expectation of the "new" stuff to be more lively. But you changed literally nothing* thus you failed your expectation. Now you will see the "new" as worse then the "old" because of it.

Sell the more expensive ones, spend the money on whatever vice you have.

*literally nothing - the actual change in bike dynamics in using 250g lighter wheels is below sensitivity of consumer measuring equipment. For humans it makes no discernable difference.
 

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Super Moderator
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The Bontrager hub has 108 POE, Vault has 120 POE. It should be fractionally better with engagement but maybe have fractionally more resistance... but I really doubt when taking into account wheel mass and tire drag it would be noticeable.

Is it because you are expecting more from the upgrades and because it didn't live up to expectation you are mentally feeling slower on it?
 

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It's a 48 pound ebike, saving 3.5 pounds by spending serous $$ on XTR breaks/drive train and race face carbon wheels is only going to make a minor difference to the ebikes performance. You might feel the difference in rotational weight of the new wheels if you pedal the bike with the motors turn off, but it's the motor doing most of the work.
 

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Out spokin'
In cog? Neato!
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Happiness = reality - expectations.

I actually made my Trek Rail a few pounds heavier than stock by installing a (far superior than stock) 210mm dropper, 29x3" tires (far more aggressive than stock), i40mm rim plus a 5mm longer stroke shock (which increased travel from 150mm to about 160mm). These changes make the bike detectably more capable(!) and therefore more fun, IMO.

But bumping component grade from SLX/XT to XTR... not so much. And yeah, no one is going to be able to detect a difference between the two wheelsets OP described, particularly on a bike that weighs over 45#.
=sParty
 

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I don't know about e bikes but on my bikes half a pound makes a big difference in wheel feel, especially sprinting from full stop. And for whips too...
 

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I don't know about e bikes but on my bikes half a pound makes a big difference in wheel feel, especially sprinting from full stop. And for whips too...
Because of the motor assistance and the bike weight, saving half a pound on wheels is going to be way less dramatic when compared to a regular pedal bike.
 

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Premium Member
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Discussion Starter · #19 ·
Because of the motor assistance and the bike weight, saving half a pound on wheels is going to be way less dramatic when compared to a regular pedal bike.
Ok Not sure if this was clear I replaced HEAVIER aluminum rims with LIGHTER Carbon wheels so they are not heavier
 
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