# mismatch tires on Ebike?



## Picard (Apr 5, 2005)

why do manufacturers install 29" tire in front and 27.5" in rear?


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## Gutch (Dec 17, 2010)

Because they claim the front will roll over more things and the back is more nimble for switchbacks etc. Also, shorter chain stays. Id try it if i wasnt buried in 29er carbon hoops.


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## Bigwheel (Jan 12, 2004)

I have been running mullet for a few years and prior to adding assist to my bike. My reasoning stemmed from the transition I made from 700c 25mm internal rims to 35mm internal rims and the resulting lower psi I was able to run going from 30psi to 15psi, as well as transitioning to tubeless at the same time after resisting that for years.

However at the lower psi I didn't like having a wide front tire as I found it grabby and not as precise steering as I was accustomed to but could feel the enhanced compliance and overall straight-line traction. After trying all the tires I had around I ended up using 2.3 tire on the 700c rim front and rear.

I was intrigued by the possibility of more traction from a wider tire in the rear and as my bike wouldn't accept a wider 700c I built a 650b i35 wheel and put a 2.8 on it and my psi test put it at the same 15psi I came to prefer in the front. Now I had precise steering with reliable traction in the front and traction and better small bump compliance due to the higher sidewalls, I ride a hardtail, in the rear. As both wheels are very close in diameter it didn't affect the bikes geo enough to tell.

I do admit that what made me originally think about it was how moto's have been setup for years with a larger rim/narrower tire in the front and a larger tire on a lesser diameter rim yet both fairly close to the same diameter for years and in fact tried out the concept when 29" wheels first came out on a DH sled with a 26" rear.









Why the manufacturers decided to go that route I don't know but I wouldn't discount the moto theory along with the fact that their testing proved positive.


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## Harryman (Jun 14, 2011)

Gutch said:


> Because they claim the front will roll over more things and the back is more nimble for switchbacks etc. Also, shorter chain stays. Id try it if i wasnt buried in 29er carbon hoops.


Steber was also claiming that with the Tazer, with the increase in torque that having a bigger footprint out back enabled better climbing traction without spinning out.

Flavor of the month, or a legit reason? Time will tell.


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## Gutch (Dec 17, 2010)

Sounds about right, everybody start switching! We need revenue! I’m still getting smoked by 26ers!!


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## ozzer (Jul 2, 2004)

Harryman said:


> Steber was also claiming that with the Tazer, with the increase in torque that having a bigger footprint out back enabled better climbing traction without spinning out.
> 
> Flavor of the month, or a legit reason? Time will tell.


It's interesting that almost all other eBikes I test rode (Focus, Levo, Pivot, Trek, COmmencal) with same wheel sizes front and back, they all have this tendency to break traction upfront while going uphill on a turn (regardless of the gradient). It's compounded when on Trail mode too. I don't like climbing slow as I still want a good workout. I like keeping my average at 12-14 mph uphill. So slowing down or washing out the front was quite annoying. I didn't find this as an issue on my Intense Tazer (which I finally bought after a much prolonged test ride). Just still getting used to the pot-belly look of the frame. Otherwise, I've split my time more on the Tazer than my other analog bikes -guilty as charged..lol


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## levity (Oct 31, 2011)

I also mismatch wheel sizes and tires for some of the same reasons discussed above. Really like the handling. The pic below shows my Levo with a 29x3 XR2 in front and a 27.5x3 Bulldozer in back. I now run a 29x3 XR4 up front and a 27.5x3 Purgatory Grid in back. I put the flip-chip in the high position to "level" things out and to provide a bit more ground clearance.

I even prefer the "975" set up on my 2017 Stumpjumper with an 29x3 XR2 up front and 27.5x3 Rocket Ron in back (lighter tires for the non-e bike). The '17 Stumpy doesn't have a flip-chip so I dropped the fork travel from 150mm to 140mm so the front end wasn't too high.


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## Bigwheel (Jan 12, 2004)




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