26" wheel in a 27.5" frame

[Blunderbuss]

I have got a 27.5" donor frame for my next ebike project and I had a severe bout of impatience, knowing that my controller would be several weeks in delivery from a far off land, and even thou my local independent bike shop would turn around getting my new 350W Bafang into a 27.5 wheel very quickly i was suffering badly.

So I stripped my Muddy Fox of its bits, bought the biggest fat tyre my local Halfords had for my 26" 500W Bafang and installed it in the Carrera Vulcan donor frame - and had a blast this afternoon.

I know that i will have lowered crank clearance by a few mm (the front wheel is still 27") but i am now wondering if i should leave this bike setup as it is (maybe even get a fatter tyre). With the rear tyre run a a lower pressure it seems just as comfortable as the Muddy Fox with its rear suspension - and i have lowered the overall weight to 23.5KG, which is a 4KG reduction (the weight penalty of the rear suspension)

Does anyone have any experience of running a bike with different size wheels, did it cause any problems?

 

[anotherkiwi]

I was going to do this with my Mxus 26" wheel and a 270€ Decathlon 27.5 bike. I still like the idea and your photo proves that it looks OK.

 

[Gringo]

And why not, after all the concept of running a larger front wheel is not a new one & it makes even more sense with a powered rear wheel.

The home built 69er (26" rear & 29" front) has been around for years and Trek even built one !
I've always liked the idea, kinda reminds me of my old trials & trail bike days

Advantages,
larger front wheel rolls faster & a smaler rear accelerates quicker
Not realy any down side apart from carring two sizes of spare inner tubes

 

[awol]

I have got a 27.5" donor frame for my next ebike project and I had a severe bout of impatience, knowing that my controller would be several weeks in delivery from a far off land, and even thou my local independent bike shop would turn around getting my new 350W Bafang into a 27.5 wheel very quickly i was suffering badly.

So I stripped my Muddy Fox of its bits, bought the biggest fat tyre my local Halfords had for my 26" 500W Bafang and installed it in the Carrera Vulcan donor frame - and had a blast this afternoon.

I know that i will have lowered crank clearance by a few mm (the front wheel is still 27") but i am now wondering if i should leave this bike setup as it is (maybe even get a fatter tyre). With the rear tyre run a a lower pressure it seems just as comfortable as the Muddy Fox with its rear suspension - and i have lowered the overall weight to 23.5KG, which is a 4KG reduction (the weight penalty of the rear suspension)

Does anyone have any experience of running a bike with different size wheels, did it cause any problems?

Anybody know if this bike is suitable for a BBSxx motor? I'm thinking of making an offroad emtb conversion and like the look of this one.

 

[RobF]

And why not, after all the concept of running a larger front wheel is not a new one & it makes even more sense with a powered rear wheel.

The home built 69er (26" rear & 29" front) has been around for years and Trek even built one !
I've always liked the idea, kinda reminds me of my old trials & trail bike days

Advantages,
larger front wheel rolls faster & a smaler rear accelerates quicker
Not realy any down side apart from carring two sizes of spare inner tubes

Some Schwalbe tubes are marked for a wide range of wheel diameters and tyre widths.

The OP is using 26" and 27.5", one tube would fit both.

 

[Blunderbuss]

And why not, after all the concept of running a larger front wheel is not a new one & it makes even more sense with a powered rear wheel.

The home built 69er (26" rear & 29" front) has been around for years and Trek even built one !
I've always liked the idea, kinda reminds me of my old trials & trail bike days

Advantages,
larger front wheel rolls faster & a smaler rear accelerates quicker
Not realy any down side apart from carring two sizes of spare inner tubes

Good point on the trial bike - and its not like i have created a clone of a penny farthing.

I did take both size of tubes with me, but never thought that the 26" would probably do both - so i have just inflated one and it looks like it would do the job. I may put a 27.5" back in when i got back home, but only needing to remember to take one size as a spare helps.

 

[Blunderbuss]

Anybody know if this bike is suitable for a BBSxx motor? I'm thinking of making an offroad emtb conversion and like the look of this one.

That was going to be my build, but i am bit of a "lazy peddler" and do not change gears as i think would be needed to keep within a certain range of rpm to get the most from a mid drive, but everything i could check looked like BBS's would fit fine. If you do this project i would be really interested to know how it works out.

 

[awol]

That was going to be my build, but i am bit of a "lazy peddler" and do not change gears as i think would be needed to keep within a certain range of rpm to get the most from a mid drive, but everything i could check looked like BBS's would fit fine. If you do this project i would be really interested to know how it works out.

I see you have the bike in your avatar. How does the bike handle off road stuff like in the background of your avatar or maybe a bit rougher?

 

[Blunderbuss]

I see you have the bike in your avatar. How does the bike handle off road stuff like in the background of your avatar or maybe a bit rougher?

I only ride off-road on tracks, byways, old railway lines (and in the avatar picture an old Roman road) so the Avatar is middling of the terrain I do. My opinion is that it handles really well, from going over the grooves left by tractor tyres (which were a bone shaker on my Argos Muddy Fox) to the lose gravel/rubble that farmers use to repair farm tracks. I max out at about 20mph because of the terrain, but am mostly doing 5 to 15mph. The saddle is the one thing that I have a beef with – after 20 miles I was suffering because it is a bit narrow, but that is easily solved.

My one is an 18” frame and you can see from the picture I had to lose the top off the 10AH bottle battery to fit it in (waterproofed with some electricians tape at the moment) so I will need to make a cap/nose cone to protect the innards. The front suspension is great (I have the pretensioner turned up to near max) and with the fat tyre on the rear it handled the ruts very well, I may need a couple of extra PSI as I did feel it drift a little when cornering on the hard surfaces at speed – but nobly tyres have a tendency to do that anyway; all in all I am a very happy ebiker.

 

[awol]

I only ride off-road on tracks, byways, old railway lines

You've described pretty much exactly what I will want the bike for.