650B / 27.5 buyers beware

[Dicky DQ]

I saw something interesting the other day and thought ...... buyer beware.

 

some newbies are being conned, well maybe. I have seen some people believing they have purchase New 650B / 27.5 bikes, but looking at them they are in fact 26" frames with 650B wheel-sets. 

 

Please check closely or you could run into trouble when trying to put wider tires on as there is not enough clearance, and riding in the mud is going to be a nightmare. 

 

Not to mention the fact that you would probably have paid a premium for the NEW standard .....

 

Just saying, be aware out there.

[Saag]

Cant trust anyone these days....what a shame!

 

For some folks it doesn't matter (know a guy that does not even know what his silverback is called!), but really sellers (people), grow a conscious, and remember Karma is a  !!!

[kosmonooit]

Nothing wrong with the conversions as such (I have 2x), besides the sometimes tricky tire clearances and size limitations. The sellers should be upfront but the buyers should also do their homework, easy enough to see if that model came out in 650b.

[Plentipotential]

Surely the geometry is different? Selling a 26 frame with 27.5 wheel set and telling the buyer it's a 650B is fraud is it not?

[worriesnot]

sjoe.... cheeky cheeky that move...

where did you see it? 

[Eugene]

Actually, I saw a well know manufacturer doing just that. The ad was big and bold advertising a 650b frame and when it was opened, there was a little disclaiming saying they were 26inch capable of fitting 27.5inch.

 

I'm running a 26 inch with 650b wheels and no problems at all.

[kosmonooit]

Surely the geometry is different? Selling a 26 frame with 27.5 wheel set and telling the buyer it's a 650B is fraud is it not?

 

Most of the time not an issue, check out the dedicated section on mtbr.com

[Eugene]

Surely the geometry is different?

The geometry refers to the angles of the frame, bigger wheels will not affect that at all. 

[Skylark]

If it is a 26" with 27.5" wheels and it's a 2hnd bike the seller should definitely mention that?

[Brian Fantana]

The geometry refers to the angles of the frame, bigger wheels will not affect that at all. 

 

Bigger wheels can affect the geometry in the following ways:

 

• The bottom bracket will be higher, which will change the handling of the bike
• If you fit a 650b fork and the axle to crown distance is longer than the original 26" fork the head angle will be slacker and the wheelbase will be longer.  This will also drop the BB slightly, but the bigger wheels will lift the BB as well, so maybe the effective height might stay the same.
• The bigger wheels will affect the down tube clearance when the bike bottoms out, especially on frames with steep head angles.

So, yes the physical angles and lengths of the structural members that form the frame does not change but the geometry of the "system" on the trail does change.

[CdT85]

Actually, I saw a well know manufacturer doing just that. The ad was big and bold advertising a 650b frame and when it was opened, there was a little disclaiming saying they were 26inch capable of fitting 27.5inch.

 

I'm running a 26 inch with 650b wheels and no problems at all.

 

Seeing that we are on the topic of 26" being modified to 650B...(due to the insanely difficult mission to find higher end 26" tires) I have the stupid idea to convert my hardtail to 650B. So far it looks like all will fit with enough clearance. How can I verify if my planned conversion will work?

[Wyatt Earp]

The geometry refers to the angles of the frame, bigger wheels will not affect that at all. 

Sure the angles will remain unchanged, but what about the bottom bracket height, the centre of gravity .

[Wyatt Earp]

If it is a 26" with 27.5" wheels and it's a 2hnd bike the seller should definitely mention that?

What do you think ?

[fabs]

Seeing that we are on the topic of 26" being modified to 650B...(due to the insanely difficult mission to find higher end 26" tires) I have the stupid idea to convert my hardtail to 650B. So far it looks like all will fit with enough clearance. How can I verify if my planned conversion will work?

Hello Otero.

Its not a crazy idea at all.

You need to check two things ...

your brake pads are able to work on the new rim?

your front tyre does not bottom out on the fork?

 

If these work, go for it.

Your overall bike geometry does not change.

The raising of your centre of gravity by 19mm due to your larger wheels will not be perceptible to you, unless you are an expert.

Have fun

 

(edit - flamesuit ON )

[nolipoli]

Bigger wheels can affect the geometry in the following ways:

 

• The bottom bracket will be higher, which will change the handling of the bike
• If you fit a 650b fork and the axle to crown distance is longer than the original 26" fork the head angle will be slacker and the wheelbase will be longer.  This will also drop RAISE the BB slightly, but the bigger wheels will lift the BB as well, so maybe the effective height might stay the same. Overall higher BB which affects handling
• The bigger wheels will affect the down tube clearance when the bike bottoms out, especially on frames with steep head angles.

So, yes the physical angles and lengths of the structural members that form the frame does not change but the geometry of the "system" on the trail does change.

 Fixed it for you.

Also if they don't fit a 650B fork, the offset of teh 26" fork is not adjusted for bigger wheels and will affect the trail, whic affects steering response.

[Brian Fantana]

 Fixed it for you.

Also if they don't fit a 650B fork, the offset of teh 26" fork is not adjusted for bigger wheels and will affect the trail, whic affects steering response.

 

That is correct.  My mind was definitely mixed up when I typed that.  The longer axle to crown distance will definitely raise the BB and change the head angle, something the frame might not be designed for.