Notices
Cyclocross and Gravelbiking (Recreational) This has to be the most physically intense sport ever invented. It's high speed bicycle racing on a short off road course or riding the off pavement rides on gravel like : "Unbound Gravel". We also have a dedicated Racing forum for the Cyclocross Hard Core Racers.

Should I get 650b wheels?

Old 03-03-21, 10:08 PM
  #1  
Cyclist0108
Occam's Rotor
Thread Starter
 
Join Date: Jul 2013
Posts: 7,248
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 2,331 Times in 1,164 Posts
Should I get 650b wheels?

Here is my geometry, relative to 700c:

I currently have 38mm tires, 700c wheels. I am pondering a second set primarily for off-road, which might enable using marginally wider tires (maybe 42 or 44mm).

Should I worry about BB clearance and pedal strikes:


Cyclist0108 is offline  
Old 03-03-21, 11:11 PM
  #2  
Cyclist0108
Occam's Rotor
Thread Starter
 
Join Date: Jul 2013
Posts: 7,248
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 2,331 Times in 1,164 Posts
Crank arms are 172.5 mm fwiw.
Cyclist0108 is offline  
Old 03-03-21, 11:32 PM
  #3  
Russ Roth
Senior Member
 
Join Date: Dec 2019
Location: South Shore of Long Island
Posts: 2,762

Bikes: 2010 Carrera Volans, 2015 C-Dale Trail 2sl, 2017 Raleigh Rush Hour, 2017 Blue Proseccio, 1992 Giant Perigee, 80s Gitane Rallye Tandem

Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1073 Post(s)
Liked 999 Times in 710 Posts
I wouldn't drop a wheelsize for that small a tire increase though mostly due to cost. The 650b is a 586 diameter while the 700c is 622, so that moves the BB and pedals 18mm closer to the ground, your new tire size only makes up about 6mm of that leaving you 1/2" lower or more. Where the more typical is to get a tire at least a 1/2" bigger. My gravel is 29x2.1 or 27.5x2.6, still a touch lower but not a lot. Most bikes meant to make the jump will allow this kind of tire difference.
But, I've dropped wheelsizes for various reasons and haven't noticed a real handling issue, I do prefer to have smaller cranks if doing so but where and how you ride will determine if it is a problem.
Russ Roth is offline  
Likes For Russ Roth:
Old 03-03-21, 11:48 PM
  #4  
mstateglfr 
Sunshine
 
mstateglfr's Avatar
 
Join Date: Aug 2014
Location: Des Moines, IA
Posts: 16,538

Bikes: '18 class built steel roadbike, '19 Fairlight Secan, '88 Schwinn Premis , Black Mountain Cycles Monstercross V4, '89 Novara Trionfo

Mentioned: 123 Post(s)
Tagged: 0 Thread(s)
Quoted: 10902 Post(s)
Liked 7,393 Times in 4,148 Posts
So you currently have 97mm of space between the ground and your crank arm.

Your wheel and tire are currently about 698mm in diameter.
650b x 44mm tire has a 672mm diameter.

So that's a 13mm drop in bottom bracket height and you now have about 84mm of crank arm clearance.


My crank arm clearance is 101mm and I manage to get some rock strikes on roads(from them bouncing up, I'm sure). I wouldn't want drop my BB lower, but if I rode smooth dirt roads then maybe it would work well.
Not sure what sort of surface you ride.
mstateglfr is offline  
Likes For mstateglfr:
Old 03-04-21, 02:48 AM
  #5  
base2 
I am potato.
 
base2's Avatar
 
Join Date: Jun 2015
Location: Pacific Northwest
Posts: 3,074

Bikes: Only precision built, custom high performance elitist machines of the highest caliber. 🍆

Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 1765 Post(s)
Liked 1,579 Times in 911 Posts
From a tire width perspective I wouldn't bother. A lot of cost for not very much benefit.

From a pedal strike perspective, is that 13mm height change going to make a difference? That depends on how you ride. Pedal strikes have a way of launching you off the bike in very unpleasent ways. I had a bike shop install an eccentric the wrong way 'round one time. They installed it so the bb being adjusted was between 3&6&9 o'clock instead of the usual upper half of around 12 o'clock. It took 3 pedal stikes that resulted in unscheduled stops into a drainage ditch, juniper bushes, & a face plant into a gravel patch before We figured out the mechanics error.

The difference of center minus 13mm & center plus 13mm was/is huge IME...Yours may be different, though.

If you happen across a decent wheel set for a good deal or free? Sure. Otherwise, I'm not sure it'd be worth it. 38 such a good well rounded compromise, it's a tough size to beat unless you have a very specific goal to optimize for.
__________________
I shouldn't have to "make myself more visible;" Drivers should just stop running people over.

Car dependency is a tax.
base2 is offline  
Likes For base2:
Old 03-04-21, 06:15 AM
  #6  
GrainBrain
Senior Member
 
GrainBrain's Avatar
 
Join Date: Aug 2017
Location: Central Io-way
Posts: 2,655

Bikes: LeMond Zurich, Giant Talon 29er

Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 1218 Post(s)
Liked 609 Times in 458 Posts
Edited to say that I did notice a difference in switching from a "38mm" tire to a 40mm tire. I didn't think handling/traction/comfort wise it would be that big of a difference but it is. If you go to a 42 or 44 you will notice an improvement if you want that wide tire ride.

I've thought about this as well, I just got a second 700c wheelset for cheap but maybe I should have gone for 650b. However my bike has a 61mm BB drop and is built around the ability to use both wheel sizes. So as others point out maybe your bike isn't a great candidate for it. Anyway here's my thoughts about 650b...

Going from a tire marked as 38mm(but 40mm measured) to a 40mm marked tire the width was the same but the diameter seemed to increase. It's made my over all gearing a touch higher then I need for gravel; and the effort needed to accelerate the tire vs a 32mm seems higher.

So maybe I should've gone with 650b? Lighter, stronger tire then 700c; or I could've gone with a 24h spoke count and had comparable strength as my 28h 700c but even lighter weight. Lower gearing. Faster acceleration?

I've heard that 650b is "slower" or feels "slower" but at these sizes a 40mm 700c takes a bit of effort to stay rolling as well.

Last edited by GrainBrain; 03-04-21 at 06:22 AM.
GrainBrain is offline  
Likes For GrainBrain:
Old 03-04-21, 07:14 AM
  #7  
blakcloud
Senior Member
 
blakcloud's Avatar
 
Join Date: Aug 2007
Posts: 2,595
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 608 Post(s)
Liked 352 Times in 225 Posts
This fear of pedal strike is so overrated. Even mountain bikes with high bottom brackets can get pedal strike depending on the size of the rocks they are going over. You don't hear mountain bikers complain because they have learned a skill called "choosing your line". Second, don't pedal when turning. In worst case scenarios there is ratchet pedaling to get you over rock piles.

I would have no problem going to 650b if I needed 42mm tires. I would get the comfort but I would just have to be more cognizant of what I was riding over.

With that said the replies above are well thought out. Pros and cons to everything.
blakcloud is offline  
Likes For blakcloud:
Old 03-04-21, 09:28 AM
  #8  
unterhausen
Randomhead
 
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 24,364
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 3,664 Times in 2,497 Posts
I don't worry too much about pedal strike, crank arm strike does bother me a bit. I don't do that much gravel riding in big rocks, but I've never had any problem just riding through it when my pedal hit. The rear wheel just came up off the ground, which is no big deal at 4mph when this happens.
unterhausen is offline  
Likes For unterhausen:
Old 03-04-21, 09:45 AM
  #9  
D@vid
Junior Member
 
D@vid's Avatar
 
Join Date: Feb 2021
Location: London
Posts: 16
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Liked 7 Times in 5 Posts
Re: cost to benefit, it depends. If you are (as everybody seems to be assuming) replacing your 700c set then it's probably not worth it. But if you want to get a second wheelset to supplement your current wheelset then it makes sense. Lots of gravel riders run two wheelsets because gravel bikes usually make pretty good road endurance or mixed surface bikes as well. So a pair of 650bs with wide aggressively treaded tyres on for the rough stuff and put some road slicks or mixed tread tyres on your 700cs and you've got two bikes for the price of 1 merely by swapping whels, which is obviously a good value proposition.

Depends if you have other bikes to fill those roles though, but if so, you could sell 1 and make money on the new wheel deal!
D@vid is offline  
Likes For D@vid:
Old 03-04-21, 07:20 PM
  #10  
Cyclist0108
Occam's Rotor
Thread Starter
 
Join Date: Jul 2013
Posts: 7,248
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 2,331 Times in 1,164 Posts
Thanks for all the very helpful responses.

Briefly, it isn't a replacement, but an addition.

I used to have two wheel-sets for this bike. Both are nearly identical (WI vs CK hubs). One set got taken over by a touring bike, so I "need" a new second wheel-set.

So I was thinking about several options:

(1) Do nothing. Change tires instead of wheels when I need to.
(2) New wheels for off-road, going smaller to get a marginally wider tire.
(3) New wheels, 700C, maybe make the new ones the on-road ones.
Cyclist0108 is offline  
Old 03-04-21, 07:57 PM
  #11  
franswa
Senior Member
 
franswa's Avatar
 
Join Date: Jul 2014
Location: ATX
Posts: 1,796
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 324 Post(s)
Liked 251 Times in 105 Posts
Clearly, the answer is yes.
franswa is offline  
Likes For franswa:
Old 03-05-21, 09:20 AM
  #12  
Bingod
Junior Member
 
Bingod's Avatar
 
Join Date: Jun 2018
Location: L.A.
Posts: 139

Bikes: Giant Anyroad

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 44 Post(s)
Likes: 0
Liked 33 Times in 22 Posts
Weaving through countless rock falls yesterday brought down by the rains i struck and unclipped my pedal three times. Could I have been more careful? Yes. Did it ruin my ride - no. But with that said I'm riding 700C x 43. One question, you will go tubeless, right?
Bingod is offline  
Old 03-05-21, 12:01 PM
  #13  
covpride
Senior Member
 
Join Date: May 2007
Posts: 143
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 14 Post(s)
Liked 18 Times in 10 Posts
Personally, I would only go to 650b if you are going to go to a 47-53 wide tire, like mentioned above the minimal increase doesn't seem worth it to go to 650b to me.
covpride is offline  
Likes For covpride:
Old 03-05-21, 07:55 PM
  #14  
Cyclist0108
Occam's Rotor
Thread Starter
 
Join Date: Jul 2013
Posts: 7,248
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 2,331 Times in 1,164 Posts
One question, you will go tubeless, right?
I guess I will have to if it has hookless rims. (?)

I would only go to 650b if you are going to go to a 47-53 wide tire,
Yeah, I just don't have the clearance.
Cyclist0108 is offline  
Old 03-07-21, 11:00 AM
  #15  
Bingod
Junior Member
 
Bingod's Avatar
 
Join Date: Jun 2018
Location: L.A.
Posts: 139

Bikes: Giant Anyroad

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 44 Post(s)
Likes: 0
Liked 33 Times in 22 Posts
[QUOTE=wgscott;21954257]I guess I will have to if it has hookless rims. (?)

I apologize if I'm stating the obvious, but I think you will want to, to get the benefits of the wider tire. Stan's rims ( what i use) have a tiny hook, but are essentially hookless, i have run them with tubes as well. I cant speak for other brands.
Bingod is offline  
Likes For Bingod:
Old 03-07-21, 08:42 PM
  #16  
Cyclist0108
Occam's Rotor
Thread Starter
 
Join Date: Jul 2013
Posts: 7,248
Mentioned: 61 Post(s)
Tagged: 0 Thread(s)
Quoted: 2366 Post(s)
Liked 2,331 Times in 1,164 Posts
Thanks.

So do hookless rims preclude you from running tubes, or do they just require that you use tubeless-compatible tires (which is what I thought)?

The only thing I have run tubeless on so far is my 2.8" mtn bike tires.
Cyclist0108 is offline  
Old 03-08-21, 10:29 AM
  #17  
nagakuraruan
Junior Member
 
Join Date: May 2017
Location: California
Posts: 10

Bikes: 2020 Julianna Quincy

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
Yes, I think the pedal strike concern is definitely overblown.
nagakuraruan is offline  
Old 03-09-21, 01:08 PM
  #18  
Bingod
Junior Member
 
Bingod's Avatar
 
Join Date: Jun 2018
Location: L.A.
Posts: 139

Bikes: Giant Anyroad

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 44 Post(s)
Likes: 0
Liked 33 Times in 22 Posts
Originally Posted by wgscott
Thanks.

So do hookless rims preclude you from running tubes, or do they just require that you use tubeless-compatible tires (which is what I thought)?.
This makes sense to me. Just match TLR tires with tubeless ready rims and then you have the option.
Bingod is offline  
Old 04-05-21, 05:23 PM
  #19  
dvdslw
Senior Member
 
Join Date: Oct 2013
Location: Apopka, Florida
Posts: 1,476

Bikes: Santa Cruz Stigmata

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 202 Post(s)
Liked 30 Times in 20 Posts
Originally Posted by wgscott
Thanks.

So do hookless rims preclude you from running tubes, or do they just require that you use tubeless-compatible tires (which is what I thought)?

The only thing I have run tubeless on so far is my 2.8" mtn bike tires.
The biggest concern for hookless rims is the bead construction of the tires which must be a strong re-enforced bead (Conti's are a no-go) and you must limit your air pressure as to not blow the tire off the rim. Tubeless is the only way to go with hookless in my opinion.
dvdslw is offline  
Likes For dvdslw:
Old 04-06-21, 01:27 PM
  #20  
Hmmm
Full Member
 
Hmmm's Avatar
 
Join Date: Nov 2014
Location: Paris, France
Posts: 399

Bikes: TCX & CAAD3 SAECO

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 147 Post(s)
Liked 118 Times in 66 Posts
I changed from 700x40's to 700x45's and felt a massive difference. I do not have experience in 650b sizes.
Hmmm is offline  
Old 04-06-21, 01:43 PM
  #21  
Darth Lefty 
Disco Infiltrator
 
Darth Lefty's Avatar
 
Join Date: May 2013
Location: Folsom CA
Posts: 13,775

Bikes: Stormchaser, Paramount, Tilt, Samba tandem

Mentioned: 72 Post(s)
Tagged: 0 Thread(s)
Quoted: 3126 Post(s)
Liked 2,102 Times in 1,366 Posts
I vote no. Benefit of fatter tires canceled out by smaller wheels.

And it will look funny.
__________________
Genesis 49:16-17
Darth Lefty is offline  
Old 04-07-21, 02:29 AM
  #22  
Badger6
Obsessed with Eddington
 
Badger6's Avatar
 
Join Date: Jun 2013
Location: Brussels (BE) 🇧🇪
Posts: 1,330

Bikes: '16 Spesh Diverge, '14 Spesh Fatboy, '18 Spesh Epic, '18 Spesh SL6, '21 Spesh SL7, '21 Spesh Diverge...and maybe n+1?

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 532 Post(s)
Liked 621 Times in 368 Posts
What is your intended use? Off-road is a wide open description. Do you literally mean off-road like single track and MTB trails....650b will undoubtedly improve your experience, both cushioning the rocks and roots while improving overall grip and spinning up faster. Or do you mean off pavement, like gravel roads in forests...stick with 700c and perhaps go to a slightly wider tire as others have recommended, it'll roll faster with less resistance. I personally do not own a 650b set because it wouldn't make sense for most of my gravel riding (the latter), but when I move back to the US, I may reconsider as a lot of what is called gravel where I intend to retire is more of the former or becomes like the former even if it is classified as a road.

Last edited by Badger6; 04-08-21 at 03:22 PM. Reason: typo
Badger6 is offline  
Old 04-08-21, 02:16 PM
  #23  
dougphoto
Senior Member
 
Join Date: Jul 2004
Posts: 526
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 130 Post(s)
Liked 24 Times in 12 Posts
I'd vote no, I had 650bs for a few yers, I got sick of the limited options for tires with 650bs. I'm back on 700's now and I have all the tire option I could dream of.
dougphoto is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.