# Rim type and width 650b



## pontoon (Aug 4, 2015)

Hi I'm thinking about going tubeless on my commuter/audax bike/light tourer/fun rides bike. I'm doing 650b/27.5. I'm wondering should I get a 25mm rim or 30mm rim? Also should I get clincher (with a rim hook) or hookless rim? I understand both work for tubeless but I may have an easier time with the hookless rim (and may save some weight with less rim strips). Right now I'm thinking of running Kojak tires in 1.35"/35mm. Perhaps I might want to go up or down from there at some point. Not sure if the higher PSI would interest me. I could also see myself running the wheels with tubes instead of tubeless at some point if that affects the answer. What would you recommend for rim width and rim hook type?


----------



## MMsRepBike (Apr 1, 2014)

? Are you talking about a mountain bike or something?

We don't use 650b wheels on road bikes, well 99.99999% of us don't.


----------



## ergott (Feb 26, 2006)

35mm isn't that wide for 650B rando style. You don't mention, but I'm guessing you have rim brakes? It's getting harder to find rim brake rims now. I would use the Pacenti SL23 which will by a great match.

If you have disc brakes that opens up the options. The Pacenti SL25 is great and WTB makes a few excellent options. For carbon I have Nox Composites on my 650B bike and I'm running Soma Grand Randos which are 42mm. The nice thing about 42mm is it's about the same overall diameter as 700X23 so you don't change the height of the bike. Not sure what kind of bike you are doing this with.

Unless you are using a true tubeless tire I would stick with bead that has a hook. I'm pretty sure the Kojak isn't a tubeless tire. Be cautious of how much pressure you plan to use. It might be simpler to just stick with tubes.


----------



## ergott (Feb 26, 2006)

MMsRepBike said:


> ? Are you talking about a mountain bike or something?
> 
> We don't use 650b wheels on road bikes, well 99.99999% of us don't.


It's quite common for 650B wheels on the bike he describes. I have one.


----------



## velodog (Sep 26, 2007)

MMsRepBike said:


> ? Are you talking about a mountain bike or something?
> 
> We don't use 650b wheels on road bikes, well 99.99999% of us don't.


I do.


----------



## dcgriz (Feb 13, 2011)

Most 650b setups I am aware of use 42mm tires; a lot of the GB Hetre and the newer Compas Babyshoe. The 35mm you are referring to is kinda narrow for the 650b, at least of the point of view of maximizing the air volume - reducing air pressure. Of course there are exceptions to that - like a very small size bike - but typically most folks gravitate to 650B/wide tires for extra comfort on extended trips on not so good tarmac.
On my Rando bike I have 700c wheels and 32mm tires which is the largest width i would put on and still maintain the "road tire" feel.

Most people I associate with that have Rando 650B style bikes would not put on anything less than 38mm tire width.

Rims wise, i would stay with the non-tubeless (with hook) rim for the ease of fixing a flat in the middle of the night if you happen to participate in brevets, etc.

In addition to the rims Ergott listed, Velocity and Grand Bois also offer 650B rims. You dont need to go with the 30mm rims.


----------



## velodog (Sep 26, 2007)

The Grand Bois are what I have on my bike and I've been pleased with them. I use the Compass Babyshoe Pass 42mm tires and they mounted easily without the use of irons.

That's using Michelin tubes.


----------



## pontoon (Aug 4, 2015)

dcgriz said:


> Most 650b setups I am aware of use 42mm tires; a lot of the GB Hetre and the newer Compas Babyshoe. The 35mm you are referring to is kinda narrow for the 650b, at least of the point of view of maximizing the air volume - reducing air pressure. Of course there are exceptions to that - like a very small size bike - but typically most folks gravitate to 650B/wide tires for extra comfort on extended trips on not so good tarmac.
> On my Rando bike I have 700c wheels and 32mm tires which is the largest width i would put on and still maintain the "road tire" feel.
> 
> Most people I associate with that have Rando 650B style bikes would not put on anything less than 38mm tire width.
> ...


When you say I don't need to go 30mm does that mean I should go 25mm? I told the rim maker to go ahead with the 25mm after doing some more reading. Hopefully this is not a mistake... Kind of looking at cross size tires I would estimate usually in the 1.1"-1.5" range( 32-40ish I think?)


----------



## robt57 (Jul 23, 2011)

If I may ask a question while I have some 650B experience/eyes here.

I just had a steel custom disc frame delivered last Friday. I had built a few 700C and a 650B wheelset in anticipation. 

Trying to figure out with zilch 650B experience what tires to use. I have 42C Conti Speeds and 27mm Vit paves for two 700 wheelsets. I did grab some used Panaracer Col De Vie Tires, 38C 650B [$20 on Craigslist] to see if I could get them to fit on my SL4 Disc Roubaix, front yes back no. The Roubaix is gone and the new frame was already ordered before I sold it with the original wheels, plan almost complete.

Sorry for the long trip around the block there. The 650B is 3/4 lower total height than the 25-700 road tires. Thinking something taller would be better due to a low BB height on the frame. Ultimately total off road tires, biggest the frame will fit for the 650 is the plan. Frame will take a 45, not sure about bigger. 

So any comments appreciated, perhaps I should have started a new thread and still can.
Apologies for drift or theft etc. But same/on topic? No?


----------



## dcgriz (Feb 13, 2011)

pontoon said:


> When you say I don't need to go 30mm does that mean I should go 25mm? I told the rim maker to go ahead with the 25mm after doing some more reading. Hopefully this is not a mistake... Kind of looking at cross size tires I would estimate usually in the 1.1"-1.5" range( 32-40ish I think?)


Yes. Anything 23mm (17mm+ interior) and over (up to 21mm interior) should be fine for tire widths between 35 and 45mm.

Which rim are you using and what exactly you plan on doing with the bike?


----------



## pontoon (Aug 4, 2015)

Thanks! It's this rim: 27 5ER 25mm Width X23MM Depth Clincher MTB Carbon Rim 650B Mountain Bike Rim | eBay

25mm exterior width carbon clincher 650b tubeless ready. I plan on mostly riding around the city for transportation purposes, plus some fun rides in the hills/mountains. I expect mostly tarmac but we'll see.


----------



## pontoon (Aug 4, 2015)

ergott said:


> 35mm isn't that wide for 650B rando style. You don't mention, but I'm guessing you have rim brakes? It's getting harder to find rim brake rims now. I would use the Pacenti SL23 which will by a great match.
> 
> If you have disc brakes that opens up the options. The Pacenti SL25 is great and WTB makes a few excellent options. For carbon I have Nox Composites on my 650B bike and I'm running Soma Grand Randos which are 42mm. The nice thing about 42mm is it's about the same overall diameter as 700X23 so you don't change the height of the bike. Not sure what kind of bike you are doing this with.
> 
> Unless you are using a true tubeless tire I would stick with bead that has a hook. I'm pretty sure the Kojak isn't a tubeless tire. Be cautious of how much pressure you plan to use. It might be simpler to just stick with tubes.


I'm using disc brakes.


----------



## ergott (Feb 26, 2006)

robt57 said:


> Sorry for the long trip around the block there. The 650B is 3/4 lower total height than the 25-700 road tires. Thinking something taller would be better due to a low BB height on the frame. Ultimately total off road tires, biggest the frame will fit for the 650 is the plan. Frame will take a 45, not sure about bigger.


My bike above has both 700c and 650b wheels. I use Hutchinson Secteurs (28mm) when I'm using 700 and Grand Rando (42mm) with 650. The ride is definitely different between the two. It's something that takes a few corners to get used to, but after that I'm fine. If I were to use 700X23 I would have the same overall diameter as the 650X42.

As stated above, I would recommend at 42mm and not much less. If the bike was originally designed around 700c you will be lowering the frame with respect to the ground. 

I do notice that overall diameter doesn't mean the two will handle the same. the 650X42 is much wider and turn in feels different. It feels more like the bike will turn in quick, but needs to be followed up with more of a counter steer in long corners than narrow tires. It almost feels like the wheel wants to continue turning in and I'm preventing that.

This phenomena could vary a lot depending on the bike and its frame/fork geometry so I can't say it's a rule. It's just something I've noticed.


----------



## pontoon (Aug 4, 2015)

ergott said:


> My bike above has both 700c and 650b wheels. I use Hutchinson Secteurs (28mm) when I'm using 700 and Grand Rando (42mm) with 650. The ride is definitely different between the two. It's something that takes a few corners to get used to, but after that I'm fine. If I were to use 700X23 I would have the same overall diameter as the 650X42.
> 
> As stated above, I would recommend at 42mm and not much less. If the bike was originally designed around 700c you will be lowering the frame with respect to the ground.
> 
> ...


I checked the BB drop and I should be safe to drop the frame a touch without serious issues. I'm planning 35mm to ensure I have enough clearance for fenders. Once I get the bike/tires shipped we'll see how much there actually is... Maybe if there's plenty I can bump up to a bigger tire.


----------



## ergott (Feb 26, 2006)

pontoon said:


> Thanks! It's this rim: 27 5ER 25mm Width X23MM Depth Clincher MTB Carbon Rim 650B Mountain Bike Rim | eBay


I think that's the same rim I know someone else that has. Similar application to what I'm doing with my bike (and I presume yours). He likes them although I'm not sure if he has those or the 30mm. If it were me, I'd choose the wider rim to mate up with 42mm tires. Less lightbulb shape to the tire. My rims are 29mm wide with the same 23mm internal width as you are looking at.


----------



## ergott (Feb 26, 2006)

What bike is it?

My bike clears 700X28 with fenders. Dropping down to the 650X42 still had plenty of room. Are you concerned with width? I also switched to 650b fenders from SKS (Longboards). The fit is very good.


----------



## pontoon (Aug 4, 2015)

It's this bike: FR602 Full Carbon Matt Cyclocross Bike Disc Brake Cycling BSA Frame Fork 51cm | eBay

I also want to keep tire size down a bit for better rolling resistance. Maybe I should have gone with 700c wheels... But I've seen some guys with 700c wheels on this bike and the tires with almost no clearance (no fenders).

Edit: here's some pics of a rider I assume using 700C and fenders. Smallish tires not lots of clearance? http://forums.roadbikereview.com/cyclocross/cyclocross-specific-chinese-carbon-287854-11.html


----------



## ergott (Feb 26, 2006)

I'm guessing that since it's a cross bike you definitely have room for 42mm. Trust me, the Crr is excellent with a good set of 42s. I have no problem riding along side the same people I usually do with that bike. A smaller tire with bad Crr will slow you down more then a fast 42. Look at Compass tires for some of the best options. Excellent tires.


----------



## ergott (Feb 26, 2006)

pontoon said:


> Edit: here's some pics of a rider I assume using 700C and fenders. Smallish tires not lots of clearance? http://forums.roadbikereview.com/cyclocross/cyclocross-specific-chinese-carbon-287854-11.html


I'm guessing those are 28s. Height won't be the problem. I'd have to see pics of the rear stays to know if width is an issue, but I doubt it. You could always wait for the frame to show up and test like you say. I just wouldn't set out using 35mm tires if I didn't have to.

There is a 38mm tire here as well.

https://www.compasscycle.com/product-category/components/tires/650b/

These are some fast rolling tires.


----------



## pontoon (Aug 4, 2015)

https://www.lfgss.com/conversations/240666/


----------



## robt57 (Jul 23, 2011)

ergott said:


> My bike above has both 700c and 650b wheels. I use Hutchinson Secteurs (28mm) when I'm using 700 and Grand Rando (42mm) with 650. The ride is definitely different between the two. It's something that takes a few corners to get used to, but after that I'm fine. If I were to use 700X23 I would have the same overall diameter as the 650X42.


Thanks




> As stated above, I would recommend at 42mm and not much less. If the bike was originally designed around 700c you will be lowering the frame with respect to the ground.


I was hoping for something even a touch taller maybe...




> I do notice that overall diameter doesn't mean the two will handle the same. the 650X42 is much wider and turn in feels different. It feels more like the bike will turn in quick, but needs to be followed up with more of a counter steer in long corners than narrow tires. It almost feels like the wheel wants to continue turning in and I'm preventing that.
> 
> This phenomena could vary a lot depending on the bike and its frame/fork geometry so I can't say it's a rule. It's just something I've noticed.


Yeah, I have owned a Buell with a 4+" wide front rim and a old Yamaha with a 2.15" wide front rim and went back and forth. Analogous I'd say.
I go from bike to bike frequently and a few are odd feeling for a mile or so. certainly as compared to my Addict which turns by thought it seems like.  Example a 70 Schwinn with 2" rake....

Thanks for your input. The 650B option was discussed with the builder. But I have zero broadness of knowledge to really have the conversation of the issues. I expect I will understand a lot more soon, empirically. 


Here is a pic, being we all love the pics... [road mode]


----------



## ergott (Feb 26, 2006)

Hmm, I don't like that slight hourglass shape to the seat stay and can't see the chainstay very well. I don't know your timeframe, but you could simply take some pieces of cardboard that's 35mm, 38mm, and 42mm wide and see what sort of frame clearance you have. Then order tires.


----------



## pontoon (Aug 4, 2015)

ergott said:


> Hmm, I don't like that slight hourglass shape to the seat stay and can't see the chainstay very well. I don't know your timeframe, but you could simply take some pieces of cardboard that's 35mm, 38mm, and 42mm wide and see what sort of frame clearance you have. Then order tires.


Should I stick with the 25mm 650b hook or should I go with 700C (and if so what rim width)?


----------



## ergott (Feb 26, 2006)

robt57 said:


> I was hoping for something even a touch taller maybe...


There is a Compass 48mm in testing that would be worth checking out when they become available.


----------



## ergott (Feb 26, 2006)

robt57 said:


> Yeah, I have owned a Buell with a 4+" wide front rim and a old Yamaha with a 2.15" wide front rim and went back and forth. Analogous I'd say.


Interesting, thanks!


----------



## pontoon (Aug 4, 2015)

ergott said:


> Hmm, I don't like that slight hourglass shape to the seat stay and can't see the chainstay very well. I don't know your timeframe, but you could simply take some pieces of cardboard that's 35mm, 38mm, and 42mm wide and see what sort of frame clearance you have. Then order tires.


Found a very clear image of the clearances! 51cm Carbon Cyclocross Disc Brake Frame BSA Lightweight Frame UD Matt Frameset | eBay


----------



## robt57 (Jul 23, 2011)

ergott said:


> Interesting, thanks!


I often run a 2mm bigger rear tire FWIW, bicycles...


----------



## robt57 (Jul 23, 2011)

ergott said:


> There is a Compass 48mm in testing that would be worth checking out when they become available.



Some googling shows the prototypes swelling to ove 50mm on those.
Have to watch for how the production runs come out in real life. I doubt
I could get a 50 on my machine, although with no knobs hanging off, time will tell.

Thanks for that...


----------



## dcgriz (Feb 13, 2011)

pontoon said:


> Thanks! It's this rim: 27 5ER 25mm Width X23MM Depth Clincher MTB Carbon Rim 650B Mountain Bike Rim | eBay
> 
> 25mm exterior width carbon clincher 650b tubeless ready. I plan on mostly riding around the city for transportation purposes, plus some fun rides in the hills/mountains. I expect mostly tarmac but we'll see.


This is what i would have picked myself as well over the wider 30 (23mm inside) rim for tire widths between 35 and 45mm. 
Considering ERTRO regulations, the 30 (23mm inside) rim shows starting at 37mm wide tires which may not mean a whole lot since there have been deviations from these stds w/o apparent adverse effects.
The narrower rim will give you more of a bulbous tire shape which is not aerodynamically desired but with 35mm+ wide tires aerodynamics is not in your list of priorities; at least would not be on mine.


----------



## ergott (Feb 26, 2006)

pontoon said:


> Found a very clear image of the clearances! 51cm Carbon Cyclocross Disc Brake Frame BSA Lightweight Frame UD Matt Frameset | eBay


I bet they would clear, but I would order tires after I at least have built wheels in the frame and can check in person. Once you have your tire size figured out, then get fenders. You don't want to order fenders only to find you want wider tires and they don't cover well.

By the way, if you are planning on running Di2, the front mech does impede clearance mounting a fender or tire with knobs. It's the first limiting factor with my frame, not the frame itself.


----------



## velodog (Sep 26, 2007)

robt57 said:


> Thanks
> 
> 
> 
> ...


Nice bike.

The only 650b tire I have any experience with are the Compass Babyshoe Pass and it's a terrific tire. They also make the extra light version but haven't tried those.

It rolls well and corners great.

The way I understand things is the larger volume tire changes the trail, but don't know how much that will affect handling.


----------



## pontoon (Aug 4, 2015)

I'm actually building up the bike now. The fenders I got, SKS Bluemells Primus 45 (P45) work, but there's pretty massive air gap (like 2cm?) even when the brake mount slots are maxed out towards the tire. Is there a way I can make the brake mounting point reach farther? Or just get different fenders? It's kind of frustrating--tempted to just say screw it and go with no fenders since I'm in California and have almost never seen rain so far (I don't know how rainy the winter will get, though, never lived through a winter here). Also to get the fit right in the rear I'd have to use about 2cm of spacers at the bottom bracket mount. Is that a bad idea?


----------

