Changing Rim Size

[Waspy]

So what would be the effect of taking a rear, geared hub motor from a 26" rim and having it laced into a 27.5" rim?

 

[Nealh]

Not a lot. Overall torque may be less but you are only talking 5 - 8% , road speed a little higher maybe 8%.
For instance a 260rpm hub in a 26" rim will acheive approx. 20mph, in 650b/27.5 form approx. 21.5mph.

 

[Waspy]

Not a lot. Overall torque may be less but you are only talking 5 - 8% , road speed a little higher maybe 8%.
For instance a 260rpm hub in a 26" rim will acheive approx. 20mph, in 650b/27.5 form approx. 21.5mph.

Thank you.

 

[Sturmey]

Dont forget, with Disk brakes, its possible to fit a 26 inch wheel into a 27.5 inch frame. The actual difference is only an inch in diameter or half inch in radius. This can be compensated for if you wish by fitting a wider 26 rear tyre. And there is no law that says the front wheel has to identically match the rear.

putting 26 inch parts on a 27.5 frame

Home › Forums › Bike Forum › putting 26 inch parts on a 27.5 frame Search Overview Chat Bike Members News Women This topic has 28 replies, 18 voices, and was last updated 5 yea…

singletrackworld.com

 

[Waspy]

Dont forget, with Disk brakes, its possible to fit a 26 inch wheel into a 27.5 inch frame. The actual difference is only an inch in diameter or half inch in radius. This can be compensated for if you wish by fitting a wider 26 rear tyre. And there is no law that says the front wheel has to identically match the rear.

putting 26 inch parts on a 27.5 frame

Home › Forums › Bike Forum › putting 26 inch parts on a 27.5 frame Search Overview Chat Bike Members News Women This topic has 28 replies, 18 voices, and was last updated 5 yea…

singletrackworld.com

Excellent, I did not think of that. The reason I am asking is if my 20 year old, 26 inch MTB craps out one day, I could upgrade to a more modern 27.5 inch, being as the bike industry have now abandoned the 26 inch format.

 

[AndyBike]

Theres not a massive difference in size. basically 3/4" all round. You can achieve similar with deeper tyres.

 

[Sturmey]

Theres not a massive difference in size. basically 3/4" all round. You can achieve similar with deeper tyres.

Its actually only 1/2 inch all round. The 26 inch rim is ISO 559mm and the 27.5 inch is ISO 584mm which is 25mm or 1 inch total difference on the rim bed/when tyre size not taken into account. The reason I think they called it a 27.5 inch rather than 27 inch which would be more accurate in our case was possibly to distinguish it from the older 27 inch standard which had incidentally a large rim (ISO 630mm) but a narrow tyre.

Wheel Size	ISO Sizes Available
26-Inch	559, 571, 584, 590, 597 mm
27-Inch	609 & 630 mm
27.5-Inch	584 mm
28-Inch	622, 635, 642 mm
29-Inch	622 mm

https://www.bikelockwiki.com/bike-wheel-sizes/