Gravelking tubeless help

[BLD 25]

Hey, all, I have a gravel/road race coming up and I need a bit of help with width and tire pressure.

Here is my setup:
Motobecane Century all-road titanium bike
tubeless capable wheels(pacenti sl23/kinlin xc279)

Gravel king sk in widths of 40c, 38c, and 35c.

I am about 186-190lbs


38mm is about the max for the rear, so I initially had 38 in the rear and a 40 in the front. Yesterday I tried a 35 in the front, and I like it.

Questions:

In a race with a mix of gravel and road, but maybe more road, what widths would be best?

What tire pressures would be best in this scenario as well?

I am thinking that I would like to err on the side of road speed instead of maximum gravel ability, and I am thinking of a 35 front, and either the 35 or 38 rear.

I really don't like a squishy feeling. I tried the 35/38 combo yesterday with about 45psi front, and 50rear, and it felt okay, but still a bit more sluggish(compared to my Supersix Evo of course).

Sorry for the long post, thanks for any help!

[AngryScientist]

you will definitely get various opinions on this, so realize this is just mine...


it totally depends on the quality of the gravel you are riding, but for courses that lean more towards blacktop, i like the 32c gravel king, which blow up to about 34mm on wide rims in my experience.

i ran GK SK for a while tubeless for a few big gravel rides and also a lot on the roads and liked them, including one all paved credit card tour on them. though the colored tires wore really fast, i think they were a great tire with a lot of capability off-road, but good on-road manners too.

so...

consider that if it's wet, you will want more clearance off-road for the mud shedding ability.

i also dont know how much you weigh or what the gravel roads you're going to see look like, but my vote is the 32c tires!

[unterhausen]

I have 38mm SK, run tubeless, and I think they roll pretty well on the road. My experience is that wider is better on gravel, but YMMV

[yinzerniner]

Have to echo earlier sentiments as it’s completely based on the course.

If you have a course map you can get an idea of tarmac vs gravel percentage, and hopefully some help on type of dirt you’d encounter. Lower pressures are great for looser stuff, but otherwise the highest pressure you’re comfortable riding with is the best for maximizing speed.

With my experience anything higher than 60psi for gk38 is overkill and the harshness of the ride makes any speed gains moot. Gk35 similar style 65psi and above. Never tried larger than those two sizes.

[BLD 25]

Thanks, everyone. I was worried 35 would be too narrow, but maybe it isn't.

I am still curious on other opinions as well.

[scoobydrew]

For mixed terrain I'd stick with 38 or 40, but it depends on what type of "gravel" you'll be riding.

I use ENVE's recommended tubeless pressure recommendations (https://www.enve.com/en/tirepressure/) as a starting point, then tweak depending on how it feels or how much road or dirt miles I'd be riding.

[cyat.es]

I run GravelKing SK 35s on my Allied All Road, and with wide carbon rims (Reynolds ATR) they blow up to about 38mm, which is the max that frame can really take.

I’m ~172 lbs and run them at 45 psi most of the time, 50% paved, 50% unpaved- of which half is smoothish dirt roads, and half is very rocky, rooty eastern MA singletrack.

I’ve considered moving to 32’s … but then I do silly things like ride down stairs or steep rock infested trails and feel better about the 35s. The performance on tarmac is pretty good. I’ve never felt uneasy on fast descents. I’m sure I’m giving up a few MPH over proper road tires … but I ride alone and I don’t really care that much. The SKs give me enough tread and cushion to do dumb things and follow trails when I want to.

[kppolich]

35s most likely. whats the road/groad split? 50/50?

[Andy sti]

What and where is the event? Maybe some others know the area and can help with your decision.

I did a gravel race last fall that was about 60 miles road and 25ish gravel. For that you needed fat gravel tires. The gravel was legit and anyone on narrow tires was really struggling. All depends on the course and the location.

[PaMtbRider]

I have Gravelking SK 38 on 30mm wide rims. They are overkill for a lot of my riding. I am still experimenting with pressure and am settling in around 32 front 35 rear. I currently weigh 180. I can't imagine running tires that wide over 45 psi. 5 psi makes a lot of difference at these lower pressures.

I have some 32c Gravelking slicks arriving tomorrow that I am looking forward to trying out.

[Davist]

Originally Posted by AngryScientist

you will definitely get various opinions on this, so realize this is just mine...


it totally depends on the quality of the gravel you are riding, but for courses that lean more towards blacktop, i like the 32c gravel king, which blow up to about 34mm on wide rims in my experience.

i ran GK SK for a while tubeless for a few big gravel rides and also a lot on the roads and liked them, including one all paved credit card tour on them. though the colored tires wore really fast, i think they were a great tire with a lot of capability off-road, but good on-road manners too.

so...

consider that if it's wet, you will want more clearance off-road for the mud shedding ability.

i also dont know how much you weigh or what the gravel roads you're going to see look like, but my vote is the 32c tires!
]

Wow, I remember why I never use colored tires, they corrode so quickly.. looks almost like dry rot around the knobs, carbon black is certainly a good thing in tire construction.

back on topic, I've used everything from 25c road tires (tour of the Battenkill) to 2.1" thunder burts, horses for courses.. Some say all you need is 28c tubular file treads, but I've found more comfort with wider tires, especially in "heavy" gravel/single track/roots/rocks or longer (>50 miles). Mud's a different thing, and perhaps we shouldn't even be riding in it (old MTB guy here, save the trails!) other than closed course or B roads.