CaptainPlanet

Found out that my old and awesome 26" mountain bike can handle 27.5" wheels, the existing v-brakes were really good but they were just shy of touching 27.5 rims to make it work.

Did manage to find some information on how to fit the v-brakes for converting to larger wheels, but those threads were almost a decade old so the parts availability have changed.

Basically it comes down to either
- buy v-brakes that can simply allows brake pads to reach higher, which models can I buy right now that's half the price of Paul motolite?
- buy brake adapters to raise the mounting point of v-brakes up by a little hit, so far found 3 types, which one is the most structurally sound and unlikely to fail? My biggest concern is that they are all made of aluminum. Option 1 looks okay because the brakes won't apply forces against the adapters, while option 2 and 3 looks like they will eventually bend out


Any other options I should try? Canada region, so shipping from US shop is not wallet-friendly

My bike was just old enough from having the disc brake mounting sockets, and disc brake adapters have been a hit or miss so not going to drop all the money for on disc brake compatible wheels and disc brakes only to find out the adapters can't do the job.

Thomas15

Just my thoughts on the matter nothing more.


I have a mountain/hybrid that has 26" wheels and V-Brakes with mounting provisions for disk front and back. About 18 months ago I went for my first ride since 2007 and even then I wasn't "riding" rather I purchased the bike, put a few miles on it (less than 200) and then hung it up in the garage.


So my first ride is with a friend that has been riding and his bike has disk brakes, 29" wheels and much better fork shocks. The extent of his off road adventures is a rail trail and that is where we rode. We did about 16 miles, he blew my doors off and I thought it a distinct possibility that I might expire trying to keep up with him. The whole experience put two things in my head. The first was I need to ride more the second I need a better bike because my friend has a better bike.


I acted on one of the two things, that is I rode more. A lot more. Left the bike as is. A few weeks ago I got together with this guy and this time I blew his doors off. I did it with V-Brakes, 26" wheels and low end shocks turned all the way up. stiff as possible.


The reason I left the bike as is is because the cost of doing any upgrades really wasn't warranted given the rest of the bike. I understand that it's fun to tinker with things and do mods and I'm not immune to doing those kinds of things. These days I have a new appreciation for what my hybrid is and even with 26" wheels, v-brakes and low end forks it not a bad bike, certainly better than anything new coming from a big box store that has 29" wheels and disk brakes.


I'm currently trying to convert a mid 80s road bike into a gravel bike. One of the problems I'm having is that the sidepull brake quick release is on the non-aero levers. I wanted to ditch those levers for inexpensive brifters. Everything was going well until I went to mount the rear sidepulls. I purchased an inexpensive set of sidepulls for the quick release feature, this after finding out that two vintage pairs I have didn't have enough reach to contact the rims. The new sidepulls because of the profile rubs the top of the tire. So I had to fabricate out of aluminum an adapter to make this all work. I have the ability to do this, had I not this mod would have been expensive.


My point in all of this is when you do these kinds of upgrades there may every well be issues that you might not see coming. So you should in my opinion weigh the benefits vs. cost ratio and see if it wouldn't be better to either do more riding with what you already have or save up and buy a bike with what you want already installed. Again food for thought.

dsbrantjr

I would say that all of the adapters would be non-starters for me, because there is little to resist the braking forces rotating the adapters outwards except for friction of the adapters against the fork. Remember there will be considerable forces acting outwards on the brake pivots which will need to be resisted by the adapters.
I would look for an adapter which is more like a brake booster, which bridges across both stud holes and will be stable against the brake reaction forces. Something like this: https://www.sjscycles.co.uk/brakes/m...black/?geoc=US tapped to mount the studs higher.

WizardOfBoz

I agree with dsbrantjr. When you bolt separate extensions to each post, applying the brakes puts a torque on each extension and they can rotate. Without positive means to resist this rotation, they WILL rotate. The horseshoe arrangement dsbrantjr points out will resist this rotation.

FastJake

Why do you want to put the wrong size wheels on your MTB?

"27.5" for mountain bike use has to be the dumbest wheel size "invention" of the past several decades. It's so close to 26" that its only purpose is to sell people new bikes.

CaptainPlanet

It doesn't look like simple brake booster could do the job for me, but the adapter on the right of the picture below would do it, but I have no idea who sells this and where to buy one.

dsbrantjr

Something on the order of the UTX-2628 is the only thing I would find acceptable. Maybe you will get lucky and someone on the forum can tell you where to find it. Where did you get the photo?

ClydeClydeson

Can someone explain the reasoning behind kludging a pair of 650b wheels onto a frame designed for 26" wheels? I see people doing this on the internet and I cannot figure out what advantage people are hoping for.

CaptainPlanet

Found that picture here but the link is dead
https://forums.mtbr.com/brake-time/2...l#post12860727

70sSanO

I think the OP is trying to build a gravel bike and not a mountain bike for singletrack and climbs. I’m not saying 26ers are better mountain bikes.

This might come under the heading of gear ratios to tire circumference. On a relatively flat surface a 29er will go faster in the same gearing, this more apparent if the max gearing on the 26er is too low.

Not even getting into smaller when requiring more revolutions at faster rate and air resistance than larger wheel.

John

ClydeClydeson

The outside diameter of the wheel determines the final drive ratio, not the diameter of the rim. ANd the outside diameter of the tire is limited by the clearance in the frame and fork, and that clearance doesn't change for different wheel sizes.

dsbrantjr

Cuz all the kool guys run 650b?

CaptainPlanet

I did read that it is possible to put wider tires on 26" rims so that 26" and 27.5" end up having the same overall diameters, but would they perform the same? Wouldn't it feel more squishy because you will be sitting on more air instead of solid?

CaptainPlanet

My issue with Mavic and Xtracycle and utx 2628 adapters is that they are for converting from 26 to 700c, and I am afraid that might be too big a jump so that the v-brake end up going up way too high. 27.5 is right between 26 and 700c. If my existing v-brake can't reach it going up, then it's not going to reach coming down either.

Although I think right now my rim brakes have more adjustment room for downward than upward, so after adapter, I maybe able to adjust down and still reach.

70sSanO

Yes. I think the consensus is that wider tires provide more cushion against rough terrain.

They also make the overall diameter larger, but I'm not aware of any high pressure tires that would be substantially taller and have a firmer ride on a 26" rim.

I guess if you are looking for lower rolling resistance, a 27.5 with a narrower tire might be the only route.

John

FastJake

More air is a good thing. You don't want to ride on something "solid." If you don't believe me, try airless tires sometime... I still don't know what you are trying to accomplish. If a firmer ride is your goal just inflate your tires more.

"Wide tires are slower." The number one myth in cycling! https://www.renehersecycles.com/12-m...es-are-slower/

Crankycrank

This is made by a company called "Mr. Control" in Taiwan. https://www.mrcontrol-bike.com/produ...n&tb=1&id=3339 Seems to be difficult to find a seller here but their website has a contact number for more info.

70sSanO

I've glanced through that in the past. I take the testimonials for very wide tires (54mm) with a grain of salt.

Not that it is relevant, but if there is no speed loss on smooth terrain with wider tires and there is truly a speed gain over rough terrain, why do the Paris-Roubaix riders not go with 40mm + tires?

That said, many years ago a neighbor of mine rode San Fransisco to Santa Monica on a mountain bike with smooth tires with a group and didn't have a problem. I will say he was an absolute monster when he got back.

John

FastJake

They're not testimonials, they're scientific tests.

The pros used to use 21.5mm tubulars. Now they're using 25s even on smooth courses. On Paris-Roubaix, 30 is becoming common. But the mainstream/pro cycling industry moves at a glacial pace. The can't just throw 40mm tires on a bike that will only fit 30mm. And making big changes is asking for trouble. ~100 years ago they resisted derailer gearing for many years.

CaptainPlanet

Revisiting this part again, if option 2 and 3 were made of tougher metals than aluminum, would they have worked better?
Maybe Homedepot might sell some similar brackets that I can use

Option 1 loos like it's just being held in place by a tiny pin, and it being made of aluminum, obviously not going to stay secured for long.
9:40 in the video

Still don't think the brake booster looking adapters would work, since they were only made for 26 to 700 conversions instead of 26 to 27.5.

One of the reasons I'd like to try the wheel conversion is because I found a pair of 27.5's for a really decent deal, so now I want to see if I can make use of them in some way.

FastJake

That's reasonable enough, but you'll still have to deal with a kludge to make it work. Are they rim-brake compatible? By the time "27.5" came around for MTBs nearly everything was disc.

dedhed

I've used these a number of times, plus they allow toeing the pads.
https://bdopcycling.com/product/bdop...s-pair-silver/


There are also these inline releases.
https://www.jensonusa.com/Shimano-CB...-Cable-Adjuste

CaptainPlanet

I need to recheck mine again. But I remember seeing GT still selling hardtail mountain bikes 27.5 with v-brakes
https://www.gtbicycles.com/can_en/palomar-2327
https://www.gtbicycles.com/can_en/laguna-2308

Miele Man

I just rebuilt a Fiori Venezia nd could not put 30mm tires on it. Some bikes will only take a maximum of 25mm tires.

I have smooth tread 1.5" tires on a 26" wheels MTB dropbar conversion and t hat bike makes a fantastic road touring bike.

Cheers

mikehuangsd

I'll add that all the little adapters below will only work if your bike has m10 size mounting posts (my Schwinn apparently has something smaller):



I ended up changing course and going with Box Three v-brakes, and they work great.

And here is the aforementioned Schwinn (a 1999 Schwinn S-40) but now with 27.5" wheels, just because I think it's a cool bike: