motor bike wheel si...
 

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[Closed] motor bike wheel size mtb relevance

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just wondering
what equivalent wheel size do motor bikes have to mountain bikes and why.
are they all the same wheel size?

do motor bikes have:
"26" wheels for easy manoeuverability and switchbacks

"650b" wheels to make the roads come alive

"29er" wheels to roll ever everything inc roadkill ?

stupid question i know, but is there any similar mtb science behind motor bike wheel size?


 
Posted : 23/03/2019 7:05 am
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They've certainly shrunk with more modern bikes and you often get a mismatch of wheel sizes too.

I prefer the bigger wheels of old personally as they tend to look better on a custom bike imho.

No idea on the science of it though. Be interesting to know.


 
Posted : 23/03/2019 7:23 am
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Generally road bikes run 17" front and rear, I'd say 95% of them anyway.
Until you get into the adventure market designed for off road, then it's things like 18-19" and 21" for clearance and rollover etc.

A few old road bikes tried and used others like an 18" on some Honda etc. But 17s have been mainstay for 20+ years.

16" were popular in racing for a whike to increase turn speed etc


 
Posted : 23/03/2019 7:27 am
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It's been 21" front and either 18" or 19" with a lower profile tyre on the rear for a long time on MX bikes.


 
Posted : 23/03/2019 7:39 am
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Old brit bikes were 19 inch just to confuse.

But as above - its settled out to 17" for road and 21 / 18 for offroad


 
Posted : 23/03/2019 8:06 am
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I was wondering why motorbikes choose a certain size and if they had any correlation to differing mtb sizes?


 
Posted : 23/03/2019 8:19 am
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Do you know why mountain bikes had 26" wheels in the first place? It didn't have much to do with science. More to do with what old road rims Keith Bontrager could find in a skip.


 
Posted : 23/03/2019 8:32 am
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That and the only wide tyres available were cruiser tyres at 26" x 2"


 
Posted : 23/03/2019 8:34 am
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Lester

Back in the day motorbikes had 19" wheels generally - up to the 60s. Suspension design was poor so the bigger wheels meant a smoother ride. Many of these old bikes were hardtails or plunger rear suspension.

18" became the norm with the japanese bikes - maybe because suspension improved so smaller more agile wheels worked?

In the sports bike era - sort of 1980 onwards wheels became smaller for faster steering going down to 16" but they were a bit too twitchy especially with the steep head angles and short trail of the race replica bikes. so 17 became the norm

Offroad - again back in the day it was 19" front and rear, then as offroad motorbikes became more developed they went to larger front wheels for better stability and better to roll over bumps. Honda even went up to a 23" front wheel for a while

Now real off roaders have settled out as 21 / 18 and Faux offroaders 19front 17 rear


 
Posted : 23/03/2019 8:40 am
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I'd like to try MX style wheel sizes on a DH bike.

A 26" rear wheel with a taller than average tyre would be great for smashing into stuff. It might get peeled off the rim on hardpack corners but modern wide rims might help with that.


 
Posted : 23/03/2019 8:53 am
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These are rim sizes you’re quoting aren’t you, not the silly nominal outer tyre diameter that we use for MTB wheels?


 
Posted : 23/03/2019 8:57 am
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Indeed - rim sizes


 
Posted : 23/03/2019 8:58 am
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One place there is a comparison is MX and enduro bikes

MX bikes designed for racing on (relatively) groomed tracks have a 19" rim with a 100/110 tyres to keep it stiff.

Enduro bikes have a 18" rim with a 120/100 tyres to resist being smashed over stuff a little more. It also helps absorb the engine vibrations a bit as they wont have a crush drive behind the sprocket.


 
Posted : 23/03/2019 9:44 am

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