Does 650B still make sense when you can fit 700x45 tyres?

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CampagYOLO
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by CampagYOLO

FlatlandClimber wrote:
Thu Oct 21, 2021 9:02 am
My take on this is a definite: "yes".
I run my gravel bike with the following four tires:
- Specialized Pathfinder Pro 42c x 700
- Pirelli Cinturato Gravel M 45c x 700
- Contiental Race King ProTection 2.1 x 650b
- Schwalbe Rock Razor 2.35 x 650b

With my gravel bike being my go anywhere machine, and my winter bike, I want it to be capable.
The Pathfinder is a great do-it-all tire, but performs best on hard pack, road, forest paths, light gravel, and cobbles.
It doesn't perform well in Sand, deep mud (especially on climbs), and when you need more cushioning (rocky or rooty descends).
The Gravel M has a more aggressive Profile, marking it perform better on mud and muddy climbs, so when it rains a lot, I tend to use this tire. This is not nearly as good as the Pathfinders on hard pack or road, but keeps you afloat on mud and sand a little better. It doesnt add noticeable cushioning.

The Conti RaceKing, a MTB tire, is one of the best tires I know. It is actually quite fast on road and hard pack, but performs better on mud than the 700c, and has a lot more cushioning. With the added width, you can run it at super low pressure, it descends well, and floats much better on sand.

The Rock Razor is really a "speciality tire" for me. It is "okay" on the road, but slow in comparison to any of the aforementioned. However, last winter it had rained for weeks on in. The forests had super deep puddles, all the mud was extremely soft, the brooks had overflowed and it was really a mess. Then, the aggressive thread and the width was a true blessing. Otherwise I just couldn't have ridden many of the paths and trails at all.
Sounds very familiar to my set up! Just substitute Vittoria Barzo's for the Rock Razors. I also agree with all your findings, I love my 2.2 Race Kings, they're by far the most versatile tyre I feel available to a gravel bike if they'll fit. Strava also shows I'm actualy not really any slower on tarmac sections despite them feeling slower.

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FlatlandClimber
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by FlatlandClimber

The one thing where I think they are notably slower than say the Pathfinders or for example a 40mm Terra Speed is aerodynamics. When I go fast into a headwind, wind turbulence on the front tire becomes very audible.
Might be a mental thing, but the 40mm-ish tires are much quieter, and I guess faster aerodynamically.
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CampagYOLO
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by CampagYOLO

FlatlandClimber wrote:
Thu Oct 21, 2021 9:44 am
The one thing where I think they are notably slower than say the Pathfinders or for example a 40mm Terra Speed is aerodynamics. When I go fast into a headwind, wind turbulence on the front tire becomes very audible.
Might be a mental thing, but the 40mm-ish tires are much quieter, and I guess faster aerodynamically.
Yeah, it's the noise that convinces me that they're slower than a narrower tyre and then afterwards I check my times on Strava and I'm not actually any slower. They're also super fast down hills in my experience, a sign of good rolling resistance perhaps.

FlatlandClimber
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by FlatlandClimber

CampagYOLO wrote:
Thu Oct 21, 2021 10:37 am
FlatlandClimber wrote:
Thu Oct 21, 2021 9:44 am
The one thing where I think they are notably slower than say the Pathfinders or for example a 40mm Terra Speed is aerodynamics. When I go fast into a headwind, wind turbulence on the front tire becomes very audible.
Might be a mental thing, but the 40mm-ish tires are much quieter, and I guess faster aerodynamically.
Yeah, it's the noise that convinces me that they're slower than a narrower tyre and then afterwards I check my times on Strava and I'm not actually any slower. They're also super fast down hills in my experience, a sign of good rolling resistance perhaps.
They pretty much the fastest knobby tire there is, especially in its width and puncture protection class.
Specialized SW Æthos (2021) 6.1kg
Specialized SW Crux (2022) 7.2kg
Specialized SW Tarmac (2022) 7.1kg
Cervelo P5 Disc (2021) 9.1kg

*all weights are race ready bikes, large frame size.
Sold: Venge, S5 Disc, Roubaix Team, Open WI.DE, Émonda, Shiv TT Disc

LeMomo
Posts: 98
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by LeMomo

For me the answer is a definite no, I changed my gravel frame earlier this year and can now fit up to 700x50mm and have fitted 700x45 G-One ultrabite for this winter, the overall diameter is a good inch larger than the 47mm Senderos I ran last year (we don't really have 'gravel' local to me and evrything turns to sloppy mud over the winter).

I'm now debating selling my 650b wheels, I do have a pair of MTB tyres that i can fit (maxxis ikon/Crossmark II combo) but if i'm riding stuff that really needs those tyres, I'm happier on my rigid B+ MTB

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justRideIt
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by justRideIt

I can confirm the love for the 27.5" Continental Race Kings. I run the 2.2" wide tires in the Race Sport version, which are veeery fluffy and smooth. Magic carpet ride, I call it.
Though the Race Sports are not tubeless ready, I run them tubeless.
Setup is not so easy, the sidewalls collapse very quickly. Also they need a lot of sealant (I use ca. 150-200ml and top up after 3-4 months) and a handful of rides until they hold air properly.

But all that is worth the ride feel. So much comfort, grip and confidence, while rolling nicely.

Currently - for fall and winter - I am on a light, (1.150g) custom-built 700c wheelset.
(Tune Prince & Princess hubs with Stans Grail CB7 rims, 20 spokes front and rear).

Sure, they accelerate noticeably faster, but on the gravel bike I care for the overall package. And there 700x40 comes short in my opinion. An additional +5mm for 700x45 would not change that.

After 8.000km since spring on the 2.2" MTB tires, I had some "WTF was that?" moments on the 700x40 the first couple of rides.
I just was not used to how the bike reacts with the skinny tires, esp. in technical terrain (singletrails with roots, stones etc.).

In the meantime, after a couple hundred kilometers on the 700x40, I have adjusted... mainly by going slower on technical stuff, or avoiding trails altogether and going for baby gravel :cry:

Cannot wait to rip off the fenders and put the 650bs on again.
Unfortunately, not enough clearance for 2.2" MTB tires and fenders.

So long story short: yeah, 650b make sense, esp. in combination with MTB tires and if you like to ride technical stuff.

Also: it looks awesome!! Just look at it :lol:

Image

Image
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CustomMetal
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by CustomMetal

justRideIt wrote:
Thu Oct 21, 2021 7:35 pm
I can confirm the love for the 27.5" Continental Race Kings. I run the 2.2" wide tires in the Race Sport version, which are veeery fluffy and smooth. Magic carpet ride, I call it.
Though the Race Sports are not tubeless ready, I run them tubeless.
Setup is not so easy, the sidewalls collapse very quickly. Also they need a lot of sealant (I use ca. 150-200ml and top up after 3-4 months) and a handful of rides until they hold air properly.

But all that is worth the ride feel. So much comfort, grip and confidence, while rolling nicely.

Currently - for fall and winter - I am on a light, (1.150g) custom-built 700c wheelset.
(Tune Prince & Princess hubs with Stans Grail CB7 rims, 20 spokes front and rear).

Sure, they accelerate noticeably faster, but on the gravel bike I care for the overall package. And there 700x40 comes short in my opinion. An additional +5mm for 700x45 would not change that.

After 8.000km since spring on the 2.2" MTB tires, I had some "WTF was that?" moments on the 700x40 the first couple of rides.
I just was not used to how the bike reacts with the skinny tires, esp. in technical terrain (singletrails with roots, stones etc.).

In the meantime, after a couple hundred kilometers on the 700x40, I have adjusted... mainly by going slower on technical stuff, or avoiding trails altogether and going for baby gravel :cry:

Cannot wait to rip off the fenders and put the 650bs on again.
Unfortunately, not enough clearance for 2.2" MTB tires and fenders.

So long story short: yeah, 650b make sense, esp. in combination with MTB tires and if you like to ride technical stuff.

Also: it looks awesome!! Just look at it :lol:

Image

Image
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Karvalo
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by Karvalo

CampagYOLO wrote:
Thu Oct 21, 2021 8:32 am
If your gravel bike is N=1 then 650x47 has roughly the same ride height as 700x28 meaning no adjustment of the seatpost each time you swap wheels.
On the other hand a completely different ride height with completely different wheel/tyre sizes also means no adjustment of the seatpost, so.....

Oms
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by Oms

gorkypl wrote:
Fri Oct 08, 2021 9:10 pm
As noted in some other thread, I am in process of designing custom frame allroad/gravel frame. My current bike cannot take more than 38mm of rubber, and this is one of the improvements I am looking forward to - I am targeting 45mm 700C tyres as max in the new frame.
I am wondering if with such capacity it still makes sense to maintain 650B tyres compatibility?

The ability to run 700C and 650B tyres on the same bike requires certain assumptions on BB drop. To accomodate 47mm 650B tyres with enough pedal to ground clearance, BB drop cannot be greater than ~70mm. On the other hand, for 700C tyres between 35 and 45mm, the optimal BB drop is between 75 and 85mm. Everything in between (like 72mm) will be a compromise of some kind.

Based on my current experiences I plan to switch between 36mm slicks for allroad touring and something like WTB Byway 44mm for all the mixed terrain.
So, do you think I could see any benefits from going even wider on 650B? Does it make any sense at all if I can run very wide tyres on 700C?
There was a point, when comparing like for like tyre widths, I decided on a 650b wheelset. There was a lack of 2x11 chainsets that had the gearing I required. A smaller wheel made for better gearing for touring /steeper gravel rides without having to compromise on my choice of groupset.

The bike was designed for them though - so BB drop is fine. Great for gravel/touring on the wider tyres. I'd say the wheels are a bit small for road riding on 28mm tyres though (prefer 700c for that).

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wheelsONfire
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by wheelsONfire

gorkypl wrote:
Fri Oct 08, 2021 9:10 pm
As noted in some other thread, I am in process of designing custom frame allroad/gravel frame. My current bike cannot take more than 38mm of rubber, and this is one of the improvements I am looking forward to - I am targeting 45mm 700C tyres as max in the new frame.
I am wondering if with such capacity it still makes sense to maintain 650B tyres compatibility?

The ability to run 700C and 650B tyres on the same bike requires certain assumptions on BB drop. To accomodate 47mm 650B tyres with enough pedal to ground clearance, BB drop cannot be greater than ~70mm. On the other hand, for 700C tyres between 35 and 45mm, the optimal BB drop is between 75 and 85mm. Everything in between (like 72mm) will be a compromise of some kind.

Based on my current experiences I plan to switch between 36mm slicks for allroad touring and something like WTB Byway 44mm for all the mixed terrain.
So, do you think I could see any benefits from going even wider on 650B? Does it make any sense at all if I can run very wide tyres on 700C?
Yes, if you rider rougher terrain it for sure is good with 650B. I would take it so far to say, buy a 650B wheelset and try it. I doubt you will regret it.
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eljamoquio
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by eljamoquio

CampagYOLO wrote:
Thu Oct 21, 2021 8:32 am
If your gravel bike is N=1 then 650x47 has roughly the same ride height as 700x28 meaning no adjustment of the seatpost each time you swap wheels.
Uh, you're changing the seatpost height relative to your wheel size? My legs stay the same length regardless of wheel size and thus I keep my seatpost at the same height regardless of tire size. I'd just assumed everyone else did the same thing too.

Tobic
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by Tobic

How wide are the 2.2" RaceKings in your hands? BRR reports about 51mm width on 17.4mm inner rim, but I recon those will come out wider if mounted onto a 25mm inner rim.
CustomMetal wrote:
Thu Oct 21, 2021 9:39 pm
justRideIt wrote:
Thu Oct 21, 2021 7:35 pm
I can confirm the love for the 27.5" Continental Race Kings. I run the 2.2" wide tires in the Race Sport version, which are veeery fluffy and smooth. Magic carpet ride, I call it.
Though the Race Sports are not tubeless ready, I run them tubeless.
Setup is not so easy, the sidewalls collapse very quickly. Also they need a lot of sealant (I use ca. 150-200ml and top up after 3-4 months) and a handful of rides until they hold air properly.


Image

Image
I've got custom 650b ti mud guards (fenders) coming for my gravel bike 🤩 best of all worlds 🥳

emotive
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by emotive

Tobic wrote:How wide are the 2.2" RaceKings in your hands? BRR reports about 51mm width on 17.4mm inner rim, but I recon those will come out wider if mounted onto a 25mm inner rim.
CustomMetal wrote:
Thu Oct 21, 2021 9:39 pm
justRideIt wrote:
Thu Oct 21, 2021 7:35 pm
I can confirm the love for the 27.5" Continental Race Kings. I run the 2.2" wide tires in the Race Sport version, which are veeery fluffy and smooth. Magic carpet ride, I call it.
Though the Race Sports are not tubeless ready, I run them tubeless.
Setup is not so easy, the sidewalls collapse very quickly. Also they need a lot of sealant (I use ca. 150-200ml and top up after 3-4 months) and a handful of rides until they hold air properly.


Image

Image
I've got custom 650b ti mud guards (fenders) coming for my gravel bike Image best of all worlds Image
According to 3T they measure 54mm on a 28mm internal rim (WAM-28) https://blog.3t.bike/2020/06/14555/what ... bike-tech/

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ryanw
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by ryanw

My 2p: 650b > 700c for gravel / off road.

Faster steering, more lively, agile, not that much slower, toe lap not as bad.

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CampagYOLO
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by CampagYOLO

eljamoquio wrote:
Thu Nov 11, 2021 3:55 pm
CampagYOLO wrote:
Thu Oct 21, 2021 8:32 am
If your gravel bike is N=1 then 650x47 has roughly the same ride height as 700x28 meaning no adjustment of the seatpost each time you swap wheels.
Uh, you're changing the seatpost height relative to your wheel size? My legs stay the same length regardless of wheel size and thus I keep my seatpost at the same height regardless of tire size. I'd just assumed everyone else did the same thing too.
Thanks for proving my point.

Switching from 700x47 to 700x28 would change the ride height, 650x47 to 700x28 doesn't.

I agree with Ryan, 650b is better if the majority of your riding is off road and incliudes a decent amount of singletrack.

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