Comfort or Crossbike?

[Tomstr]

I've been wanting a bike for gravelgrinding for some time now but now the budget is there I can't really decide on the type of bike to get.

I'm trying to decide between a comfortbike and a cross bike. Given the group, wheels, brakes are the same it's essentially a choice between geometries so which one would you go for?

For reference, my current "grinder" is a Giant TCR advanced with 25mm Michelin's (that go 28mm on the 17mm inner width rims) that does the job fine but could do with some more tyre clearance and braking.

[HillRPete]

I'd say get a vintage road frame with decent clearance and convert it to 650b, or a vintage CX bike. Stay true to the spirit of the unpaved.

As regards geometry, it depends on what you are used to, the duration of your rides, and the terrain. If you can handle road position for long hours, and the terrain does not have double-digit percentage descends on loose ground all the time, and your rides are not frequently in the double-digit hours, you can be quite efficient with a road-ish position.

Tyres is the hottest topic. As long as there is no mud or slippery dirt, no knobs needed IMO. But use the widest tyres that fit, so you have more control on the loose stuff. 35mm go a long way, but with a 650bx42 or even 50-ish (size of the smallest MTB tyres) you can just plow over everything. The latter would probably require a vintage mtb frame, they can make excellent gravel grinders with their shorter top-tubes back then, no problem fitting drop bars.

Building an '82 KHS Turbo myself right now. Spec'd for 55mm (medium reach) brakes, so decent clearance.

[Tomstr]

True words right there, thanks!.

I think you're right in saying the choice should revolve around the terrain and speed i.e. tyres and a CX bike gives much more choice in that aspect. I think I can deal with the different geometry given the fact I'm currently running a good amount of slam and drop.

By the way, a Giant Propel is fine as a gravelgrinder as long as it's not too crazy and dry. It shows that the manufacturers are leading us on with their fancy adventure bikes whereas a good set of tyres is enough to get the job done most of the time.

[HillRPete]

It shows that the manufacturers are leading us on with their fancy adventure bikes whereas a good set of tyres is enough to get the job done most of the time.

Oh I wouldn't go that far. Take my comment about vintage frames with a good deal of tongue-in-cheek. I am not against innovation at all, and it is great to see high quality parts becoming available for mixed terrain riding, not just for the various road or MTB race disciplines.

The most important thing is to feel pumped about your rig, be it vintage or modern, off the peg or custom. That makes you take it out and ride more often.

[wheelsONfire]

You have Santa Cruz Stigmata and Open Cycle "UP" / Unbeaten Path.
Both of these handles 40mm tires with ease.
I don't know if Stigmata handles 650B wheelsets, but UP does.
You mention comfort/ comfort bikes.... all i honestly can say, the comfort of an UP is surely on another level.
Partly pending on the larger tires, the seat post and saddle you go for and probably the frame (lay up).
If you guess i would say, go for a gravel, you are right.

You can tune your gravel build for comfort with choice of components.
I had this in mind when i built mine.
That is why i went for Syntace P6 HiFlex seat post, No tubes Avion (Pro) wheels and last Cobb Max saddle.
If you ride gravel, i would suggest you use tires from 34mm and wider.
There are several great tires lately!
I doubt you will regret going for a gravel bike.
You can really use different wheelsets and different tires making the bike a very all-around.
My routes always start from tarmac, then gravel and some trail.

BTW, i would just like to tell you. Cobb has a superb test program of their range of saddles.
You can also contact them and ask for advice during the testing period.

Lately there has been more 650B wheelsets handling 11 speed cassettes (road).
This you must check before purchase!

650B/27.5" wheels with UP, make it possible to use 55mm tires.

See here:
Radius Rim Tire
341mm 700c/29er 28mm road
344mm 700c/29er 32mm cross
350mm 700c/29er 40mm cross
342mm 650b/27.5" 2.1" mtb

[MikeDee]

I'd say get a vintage road frame with decent clearance and convert it to 650b, or a vintage CX bike. Stay true to the spirit of the unpaved.

As regards geometry, it depends on what you are used to, the duration of your rides, and the terrain. If you can handle road position for long hours, and the terrain does not have double-digit percentage descends on loose ground all the time, and your rides are not frequently in the double-digit hours, you can be quite efficient with a road-ish position.

Tyres is the hottest topic. As long as there is no mud or slippery dirt, no knobs needed IMO. But use the widest tyres that fit, so you have more control on the loose stuff. 35mm go a long way, but with a 650bx42 or even 50-ish (size of the smallest MTB tyres) you can just plow over everything. The latter would probably require a vintage mtb frame, they can make excellent gravel grinders with their shorter top-tubes back then, no problem fitting drop bars.

Building an '82 KHS Turbo myself right now. Spec'd for 55mm (medium reach) brakes, so decent clearance.

Yes, tire width makes a huge difference in comfort and control. I wouldn't consider a gravel bike unless it could take 45mm tires.

[wheelsONfire]

Perhaps you should use 650B/ 27.5" wheelset and then you could use more than 45mm width tires.

[junchen]

Does any modern frames allow the use of 650b.?

Sent from my SM-G920I using Tapatalk

[MikeDee]

Putting 650b wheels on a 700c does not guarantee that a fatter tire will fit. The height issue is taken care of, but not the width.

There are a number of gravel/ monster cross bikes out there that take fat tires. Giant Anyroad, Black Mountain Monstercross are a couple of examples. You can also convert a hardtail mountain bike to drop bars.

[wheelsONfire]

Does any modern frames allow the use of 650b.?

Sent from my SM-G920I using Tapatalk

Open Cycle UP/ Unbeaten Path
https://opencycle.com/up

[wheelsONfire]

Putting 650b wheels on a 700c does not guarantee that a fatter tire will fit. The height issue is taken care of, but not the width.

There are a number of gravel/ monster cross bikes out there that take fat tires. Giant Anyroad, Black Mountain Monstercross are a couple of examples. You can also convert a hardtail mountain bike to drop bars.

Not a problem with UP.
I can swear it will handle over 40mm tires with 700C rims/ wheels.
All pending on what wheels you have.

I have No Tubes Avion Pro, internall width is close to 22mm. Also, No Tubes uses their own bead hook design, so the tires shapes more like a bulb than other rim designs.
I ask Schwalbe of G-One 40mm tires size compared to the 35mm versions.
They say, 40mm version is 2.5mm + at both sides and gains 5mm on the depth over the 35mm version.
This will work even with Avion wheels.
The thing is, G-One 35mm are far fatter than other tires that are specified 36-37mm.

So, if you'd use a rim with 19mm internal rim width, it is possible you can fit a tire that is 45mm.
If it will not work, it's because of chainstays or seat tube mast.
Currently have no money for new tires, so i can't test this.

[Tamu8104]

Typically if you can fit a 40mm tire with clearance for mud than you can fit a fat 27.5. Here's some pictures of my Rock Lobster with first WTB Nano 40s and then some 27.5 Kenda 2.0s. The 2.0s would be tight if it was heavy mud but for dry(ish) trails they are a blast.







All this said, what will be best for you really depends on what your gravel is like. Most of my gravel is ridden on my other bike with Compass Bon Jons. The Lobster sees more single track.

[Tomstr]

Very good info on the wheelsizes and tyres all, thanks! That RockLobster is genius!

I went ahead and bought a Giant TCX which will fit a wide selection of tyres and sizes. As for the gravel here, it's mostly like this photo. It will get soft when really wet but otherwise fine to ride with wide slicks. Considering there are also a lot of road sections between the gravel or forest roads I can't go for knob tyres.

http://scontent.xx.fbcdn.net/t31.0-8/19 ... 9842_o.jpg

The standard wheels are HEAVY but roll very well on the maxxis mudwrestler so next up are the wheels.