[Closed] Plus tyre on a 30mm rim. Will I die?

Depends on the tyre. Might come up a bit round, but reasonable pressure and you'll be OK. 35mm would be better though.

I'm having some 29 plus rims built up, 35mm wide internally. I've been assured that they'll be fine for 3" tyres if that helps?

Context. I have 27.5+ on both main bikes (and 26+ on another). 2.8s on 30mm are OK but I've moved to 35mm as I've built new bikes/upgraded wheels. I find the front more sensitive to rim width than the rear (have still got a 30mm rim on the back of the 26+ bike). I run WTB Rangers as a rear tyre - 35mm gives a better shape and the option to run lower pressures but it's fine on 30mm with higher pressure and given the tread pattern this works OK. WTB Vigilante on the fronts are less good at 30mm but are great at 35mm.

From Maxxis

RECOMMENDED TIRE AND RIM PAIRING

Inteded Use Tire Width (in) Inner Rim Width (mm)
XC Racing 2.00 - 2.20 20 - 25
Light Trail 2.20 - 2.40 25 - 30
AM/Enduro 2.30 - 2.50 28 - 35
2.60 35 - 40
Plus 2.80 - 3.00 40 - 45
Fat 3.80 - 4.00 70 - 80
4.80 90 - 100

https://www.maxxis.com/catalog/tire-468-140-minion-dhf

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Got some 40mm internal DT XM551 27.5 rims with very little use if of interest?

When their plus bikes first came out, Specialized said they found not much detriment with the 30mm rims, and specced them across the board for weight savings.

So no, you won’t die.

Two things you would expect to be less good than with wider rims:

Rounder shape vs a flatter shape. This means cornering knobs come into play later, and any channel between center and corner knobs will be much more pronounced.

You might want to pick a tire with intermediate knobs, like a Rocket Ron, Vigilante Purgatory, Eliminator, new Nobby Nic or Hans Dampf vs something like a Minion, Magic Mary or Butcher.

The second thing would be less sidewall support at lower pressures.

Less of an issue in back, where you need higher pressures to prevent rim strikes, and a bit of squirm isn’t a big deal.

You can choose tires with stronger casings and/or run an insert like Cushcore-Plus. This will help stabilize the sidewall and prevent burping.

Both of these things also depend on your terrain and riding style. For easy cruising/bikepacking, where you are not cornering super hard, none of these matter.
For bikepark shredding, it would be a very poor choice. Go 2.6” instead.

I have 2.6 tyres on 30mm rims and they are very good - Magic Mary F and Hans Dampf R. I have the same tyres in 2.8 on 33mm rims and they are also brilliant. So I wouldn’t worry about the widths you are using OP.

The 2018/2019 Scott Genius 700s were spec’d with a 27.5 2.8 Maxxis Rekon on a 30mm internal rim from the factory

Per jamj I’m a bit dubious about those Maxxis recommendations - I’ve always found 2.6 to work really well on 30mm internal width rims. Agree 2.8 is probably pushing it a bit though....

25mm rims on 3.0 tyres here.

Just means you can't run them low. But you can be cheap.

Stan's say their flow mk3s are good up to 2.8 width, and they're 30mm internal.

Running 2.5 on 21mm width, have done for years. Max for a D521 is 3.0. As said it will round out the profile but 30mm should be fine for 2.8.

Having just switched from 40 to 35 internal IMO you can notice there is marginally less support up front. They're lovely wheels and I'm saving a ton of weight making the bike much more fun to ride so I'm happy with the compromise. YMMV. Same tyre. Dhf 2.8 fwiw. If you're building new wheels I'd go for the wider rim up front at least.

I have a 2.6 Ikon on a 29mm rim. Works well for XC riding but need to get the pressure just right.

For a while I had 2 bikes both with 3 inch rangers on 30mm rims (not by choice), it was like riding on a bouncy castle, definitely would not recommend the combo or wtb ever to be honest.

2.8 Vigilante on a 30mm rim & the profile is fine. WTB recommend 28-35mm rims on the packaging they came in. Incredible tyre in the high grip compound. I’m running the front sub 15spi for natural peaks stuff with a rimpact insert. No noticeable roll or squirm & the grip is insane. I’d bump up the pressure for bikeparky stuff with fast berms & jumps though.

Stan’s say their flow mk3s are good up to 2.8 width, and they’re 30mm internal.

29mm I thought? Either way, I've run 2.8 DHF/DHR on Flow Mk3s and they were fine

Have you run 2.8 on a 35 or 40mm internal rim?

@sillyoldman PM sent about the DT XM551s. Cheers