27.5” front 26” rear - Wheelbuilding

Eastwood

100 kW
Joined
Jan 13, 2021
Messages
1,453
Hello everyone!

So I just purchased a mxus 3k 5T motor only. I’m debating whether I should keep 27.5 front and rear but I’m also considering using 26” on the rear for a stronger wheel build and slightly more torque.

Have any of you ran a 27.5 front and 26 rear? I guess I’m leaning toward keeping the 27.5 F/R but would love to hear some feedback. Any thoughts or input on this would be greatly appreciated!

As of now I’m leaning toward lacing the hub motor with Halo Sas rim.
Thanks Guys!
 
That should work fine for most bikes; it will reduce ride height very slightly and slacken your bikes angles a tiny bit, which suits the increased speeds you'll be attaining.

If you use a significantly fatter tire in the rear than in the front, the effect on your bike's geometry with be minimized, and so will the effect on the motor.

Halo SAS is an excellent rim if its width suits the tire size you want to use (ideally about 1.75-2.5").
 
Eastwood said:
Hello everyone!

So I just purchased a mxus 3k 5T motor only. I’m debating whether I should keep 27.5 front and rear but I’m also considering using 26” on the rear for a stronger wheel build and slightly more torque.

Have any of you ran a 27.5 front and 26 rear? I guess I’m leaning toward keeping the 27.5 F/R but would love to hear some feedback. Any thoughts or input on this would be greatly appreciated!

As of now I’m leaning toward lacing the hub motor with Halo Sas rim.
Thanks Guys!
It will change your geometry, but when 29er's came out, some people converted to 29 in the front, and 26 in the rear (69er), to obtain the advantage of the larger front diameter (which helps over rough terrain).
 
That little difference doesn’t matter much. You will probably want it even slacker anyway, depending of speed and riding style. I adjust geometry with the custom dropouts that I make for any hub build. Bolt-on dropouts can be adjustable with multiple mounting options, letting you use almost any wheel size. The front can be tuned too: stanchions depth, limited travel, or Angleset headset. So, the little difference in wheel size is not limiting really, the geometry tuning potential of the bike. As Chalo noted, choice of different tires and PSI alone can make that much geometry mod on a bike.
 
Chalo said:
That should work fine for most bikes; it will reduce ride height very slightly and slacken your bikes angles a tiny bit, which suits the increased speeds you'll be attaining.

If you use a significantly fatter tire in the rear than in the front, the effect on your bike's geometry with be minimized, and so will the effect on the motor.

Halo SAS is an excellent rim if its width suits the tire size you want to use (ideally about 1.75-2.5").

OK thanks for the input! my tire is 2.8 Schwab super Moto. I had regular mountain bike tires at first but made the switch and I’m loving these tires!

Yeah slacking the head angle more would be a plus! I have dual crown downhill forks already which helped slacken the head tube angle quite a bit. More would be even better :thumb:
 
E-HP said:
Eastwood said:
Hello everyone!

So I just purchased a mxus 3k 5T motor only. I’m debating whether I should keep 27.5 front and rear but I’m also considering using 26” on the rear for a stronger wheel build and slightly more torque.

Have any of you ran a 27.5 front and 26 rear? I guess I’m leaning toward keeping the 27.5 F/R but would love to hear some feedback. Any thoughts or input on this would be greatly appreciated!

As of now I’m leaning toward lacing the hub motor with Halo Sas rim.
Thanks Guys!
It will change your geometry, but when 29er's came out, some people converted to 29 in the front, and 26 in the rear (69er), to obtain the advantage of the larger front diameter (which helps over rough terrain).

Oh nice 69er! Never heard that before :lol:
 
MadRhino said:
That little difference doesn’t matter much. You will probably want it even slacker anyway, depending of speed and riding style. I adjust geometry with the custom dropouts that I make for any hub build. Bolt-on dropouts can be adjustable with multiple mounting options, letting you use almost any wheel size. The front can be tuned too: stanchions depth, limited travel, or Angleset headset. So, the little difference in wheel size is not limiting really, the geometry tuning potential of the bike. As Chalo noted, choice of different tires and PSI alone can make that much geometry mod on a bike.

Yeah I was thinking the same, it wouldn’t make too much of a difference either size. But even more slack head angle is a plus. Now I just have to decide to keep the 27.5 or 26. The only thing is if I go to 26 I have to buy a new tire :confused:
 
I been debating making a mullet with a 26 front and 24inch rear wheel on an old dirt jumper 135mm dropout frame and run a chaindrive setup with a dual disc type hub.
Im not planning on peddling along so to much a large bike is not needed id get more fun throwing a smaller frame bike around as long as its comfortable to sit on arm reach etc and alot of that can be fettled with.
Im thinking a well balanced ebike should still enjoy a few feet air and a dirt jumper is a real good all round solid bike.
 
Mxus xf40 45h

Thats what i used and it seemed spot on dimension wise for the 3k.
They fixed the disc mount on them i found with out a spacer no chance in hell of fitting a caliper what type of design is that useless from stock and they didn't even supply one.
 
Ianhill said:
Mxus xf40 45h

Thats what i used and it seemed spot on dimension wise for the 3k.
They fixed the disc mount on them i found with out a spacer no chance in hell of fitting a caliper what type of design is that useless from stock and they didn't even supply one.

Ok thanks! Very helpful to know the xf40 45h is the same dimensions as the 3K :D what gauge spokes tho?
So are you suggesting that the new hub motors from maxus 3k they fixed the caliper mounting issue? I’ve seen this discussed several times where the caliper rubs against the hub motor.
 
Eastwood said:
what gauge spokes tho?

You're using a bicycle rim, with double eyelets, so the outer end of the spoke should be 14ga (2.0mm). You can use straight 14ga spokes, 14-15ga double butted spokes, or 13-14ga single butted spokes. Whichever of these you choose, you'll probably have to put washers under the spoke heads to keep them from pulling through the oversized flange holes in your hub motor.

14-15ga double butted spokes make the most reliable, low maintenance wheel, if you can get them in the length you need.
 
Chalo said:
Whichever of these you choose, you'll probably have to put washers under the spoke heads to keep them from pulling through the oversized flange holes in your hub motor.

OK good to know!

Chalo said:
14-15ga double butted spokes make the most reliable, low maintenance wheel, if you can get them in the length you need.

OK I’ll go with the 14ga double butted.
 
I've always tried to avoid Home Depot/Lowes or any department store for washers on the spokes. My assumptions are they are the bottom of the barrel so I've always sought out actual fastener stores that sell everything from bolts, screws, power tools, zip ties, tapes etc.

Local to me, they might ship but I've always brought my spokes in to the store so I can get a feel for how the washer is tight sliding it onto the spoke and up to the J-bend. Some spokes are straight gauge, others not so it does make a difference sliding it onto J-bend, then wiggling it to get a feel for the washer-spoke gap.

https://boltsupply.com/
https://www.fastenal.ca/
https://www.calfast.com/
http://www.questindustrial.ca/

Harbor Freight might sell washers.
 
Stainless washers probably hold up the best, i used motor bike spokes 12gauge it worked but id have to agree that 14 is better my wheel felt like it could bust through a wall and not flex very rigid ride.

Not sure if they fixed the disc brske mount about 3 years ago i done mine.
 
Ianhill said:
Stainless washers probably hold up the best,

OK good to know, I’ll go with stainless!

Ianhill said:
Not sure if they fixed the disc brske mount about 3 years ago i done mine.

Hopefully they sorted that out if not I guess spacers for the rotor.
 
Eastwood said:
markz said:
I've always tried to avoid Home Depot/Lowes or any department store for washers on the spokes.

Yea those were the first places I thought about buying washers so i’ll take a look at the links you provided.

Well those stores are localized businesses, I just gave those as examples of what Fastener stores sell, I dont know if they would ship or not, but probably. I know Fastenal doesnt want no one except commercial and industrial accounts.
 
markz said:
Well those stores are localized businesses, I just gave those as examples of what Fastener stores sell, I dont know if they would ship or not, but probably. I know Fastenal doesnt want no one except commercial and industrial accounts.

OK gotcha, i’ll try to find a local source that I can go in and test the washers with the spokes.
 
I see magura have an 220mm rotor i wonder if that would clear the hub flange enough to allow the caliper to clear with out a spacer at all.

I got an old picture of a 203mm rotor and looking at that it would be close but it might help if someone was trying to fit in a 142mm dropout, i had 150mm on the a2b metro so run a 8mm disc spacer and all equalled out fine but a 220mm disc might work on standard frames.
IMG_20190625_015137748.jpg
And if not sod the disc run an oset sprocket and 219 chain to the hub and make your tyre pop from the 20kw plus hurt bombs you drop on it.
 
Ianhill said:
I see magura have an 220mm rotor i wonder if that would clear the hub flange enough to allow the caliper to clear with out a spacer at all.

I got an old picture of a 203mm rotor and looking at that it would be close but it might help if someone was trying to fit in a 142mm dropout, i had 150mm on the a2b metro so run a 8mm disc spacer and all equalled out fine but a 220mm disc might work on standard frames.
IMG_20190625_015137748.jpg
And if not sod the disc run an oset sprocket and 219 chain to the hub and make your tyre pop from the 20kw plus hurt bombs you drop on it.

OK good to know. I run 203mm rotors F/R so hopefully it’ll be enough to clear the hub!

So my dropouts are actually the standard 135, i’m hoping to squeeze this 142mm motor in there :wink:

If I used a 4 or 5 speed Freewheel would that help lower the size of 142?

From what I’ve been reading if you use a single speed the dimension is 135mm. So that being said I might just go with a 5 speed freewheel so I don’t have to force the openings of the drop out too much.
What are your thoughts on that or if anyone can chime in?
 
Thats right rings a bell nw 150mm with a 7 speed cassette
 
I think you just need to pay attention to which you are ordering.

https://www.aliexpress.com/item/32649215681.html?src=google&albch=shopping&acnt=708-803-3821&isdl=y&slnk=&plac=&mtctp=&albbt=Google_7_shopping&aff_platform=google&aff_short_key=UneMJZVf&&albagn=888888&isSmbAutoCall=false&needSmbHouyi=false&albcp=11473778399&albag=112983073900&trgt=449349191507&crea=en32649215681&netw=u&device=c&albpg=449349191507&albpd=en32649215681&gclid=Cj0KCQjwutaCBhDfARIsAJHWnHsR2r3xSAcuA4iUphGCbg5sVg33gCIPMLb0tt5QnDqdaL3Oq_8sJeoaAuSyEALw_wcB&gclsrc=aw.ds

https://www.aliexpress.com/item/32761513299.html?src=google&albch=shopping&acnt=708-803-3821&isdl=y&slnk=&plac=&mtctp=&albbt=Google_7_shopping&aff_platform=google&aff_short_key=UneMJZVf&&albagn=888888&isSmbAutoCall=false&needSmbHouyi=false&albcp=9317063908&albag=94962804715&trgt=536572975094&crea=en32761513299&netw=u&device=c&albpg=536572975094&albpd=en32761513299&gclid=Cj0KCQjwutaCBhDfARIsAJHWnHtSvHDRMDy52Qf1lFhxfs5QL6Nrpg0rNeu1Si3B9d0UgATvu-k2N-saAsiNEALw_wcB&gclsrc=aw.ds

For myself, I would just use the 135mm version and single speed, since the motor is moving toward a throttle-most-of-the-time ebike, with a little pedaling at slower speeds for show.
 
E-HP said:
I think you just need to pay attention to which you are ordering.
Actually Both links are exact same motor. If you read the specifications One says 135mm with singe freewheel. The other link says 142mm with 6 speed freewheel. They just label the motor two different ways for marketing purposes. So basically all mxus 3K with a single speed is 135mm and then it increases once you start adding multiple gears.

Here’s the link for for the mxus I bought. I went with this seller because it was the fastest delivery. I’m supposed to receive mid April.
https://www.elecycles.com/mxus-3000w-motor-brushless-electric-bike-rear-hub-motor.html
E-HP said:
For myself, I would just use the 135mm version and single speed, since the motor is moving toward a throttle-most-of-the-time ebike, with a little pedaling at slower speeds for show.

Yeah I would just use a single speed but I do a lot of peddling when I ride on greenways and mountain bike trails. Now on the street a ride just like a motorcycle and only pedal when I see cops :lol:
 
Eastwood said:
Actually Both links are exact same motor. If you read the specifications One says 135mm with singe freewheel. The other link says 142mm with 6 speed freewheel. They just label the motor two different ways for marketing purposes. So basically all mxus 3K with a single speed is 135mm and then it increases once you start adding multiple gears.

Really? The diagrams show that the dimensions are clearly different. 134.5mm vs. 142mm

https://ae01.alicdn.com/kf/Hc71df8e652e84701908a5d01da78295fY.jpg
https://ae01.alicdn.com/kf/HTB1b3RsMpXXXXcoXVXXq6xXFXXXU/221256497/HTB1b3RsMpXXXXcoXVXXq6xXFXXXU.jpg

has nothing to do with the freewheel. it's how the axle flats are cut.
 
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