Maximum Tyre width

MattyB85

Afternoon all,

I'm the proud owner of a 2018 Giant Fathom 2. Giant supply these with Maxxis Ardent tyres in 2.25 width. They are poor in the wet/mud and feel pretty poor in anything other than completely dry conditions. I've played around with pressures but being quite a heavy guy I need to run them relatively hard.
I've been recommended some Nobby Nic's but have seen they come in a variety of widths. I'd like to go wider but not sure what the maximum is I can get away with. Schwalbe do a 2.6 Nobby Nic, anyone know if it would fit?

Cheers

robertpb

And this relatively hard is, your weight is, better to get the basics right before you start spending.

MattyB85

Sorry- relatively hard= 40 ish psi
Weight= 14.2 stone

robertpb

In the mud with your weight that size tyre tubed I'd be running around 30psi.
In the mud with a tubeless 2.35 tyre I'm down to 18psi in the front for grip.

MattyB85

Not really too fussed about what pressure's I'm running, as long as I'm running well and it all feels good when out. I know that with lower pressures I'm feeling like I'm hitting the rim on roots & rocks so keep enough in to make the ride better for me.

My question is simply what is the widest tyre I can fit on my Giant Fathom 2

JGTR

Get a ruler and measure it, just bear in mind that some tyres are slightly different from the states width, factor that into your descision.

I would also say that 40 psi may be a bit on the high side.

MattyB85

Cheers JGTR- I did wonder if the stated width and the actual width may differ- hence me asking if anyone knew for sure.

I'll get the tape measure out tonight and see what I have to play with unless anyone can answer it definitively before then.

And yeah, 40psi is high- but I'm a fat fucker at the moment so need the extra pressure to save the rims

JGTR

I’m heavier and run 25 psi on 2.4”

MattyB85

Wowzer... I always feel as if i'm smashing the rear wheel to pieces when going over roots. Currently on a 2.25 so there may be more difference than I thought in the difference in capabilities between the sizes. (also I'm not tubeless, yet)

Or perhaps you're just a little more nimble on the trails than I am...

JGTR

I’m riding 2.4” x 29” - you can run a bit lower with 29” wheels. Nimble is something that I am not

The Rookie

Probably feel like your smashing the wheel as the tyre is too hard and not absorbing anything!

I ride with a guy who’s similar weight to you, and on a fathom, he’s at 30psi, I’m only 9 pounds lighter (about 5% of the rider plus bike weight) and run 28 in the rear on a similar sized tyre.

MattyB85

The Rookie wrote:

Probably feel like your smashing the wheel as the tyre is too hard and not absorbing anything!

I ride with a guy who’s similar weight to you, and on a fathom, he’s at 30psi, I’m only 9 pounds lighter (about 5% of the rider plus bike weight) and run 28 in the rear on a similar sized tyre.

I'll give it a go... is he using the standard Maxxis Ardent's that come supplied? 27.5?

The Rookie

Yup.....

slc123

I run a set of 2.25 Ardents on my XC bike and ride in the worst conditions in muddy trails. I'm lighter than you, but tend to ride my bike pretty hard. I drop to high 20s to ride in the mud and get a decent amount of grip. There are better tyres for muddy conditions but I find these pretty all round.

mattyfez

I'm 16 stone and run 30-33 psi f/r, 40 sounds way to high to mee too.

MattyB85

slc123 wrote:

I run a set of 2.25 Ardents on my XC bike and ride in the worst conditions in muddy trails. I'm lighter than you, but tend to ride my bike pretty hard. I drop to high 20s to ride in the mud and get a decent amount of grip. There are better tyres for muddy conditions but I find these pretty all round.

mattyfez wrote:

I'm 16 stone and run 30-33 psi f/r, 40 sounds way to high to mee too.

I'll give high 20's to around 33 a go then and see how I get on. Cheers guys.

cycleclinic

are you running the tyres tubeless, if not convert and use 25 psi max. That cures all sort of problems at a stroke.

davidradar

Hello. Okay I Googled your pushbike and found it has XC-2 Rims. I am not sure if I got the correct specs from the giant website but I referenced the 29"

If you do some further research there are maximum and minimum tire width recommended by manufactures of rims. I know mine are DT Swiss and there website states this info. Just having a quick look at I would think 2.4 would be the max recommended for 19mm wide rims. I would take the previous poster advice and go tubeless if not already.


XC-1 is 23mm wide
XC-2 is 19mm wide

MattyB85

thecycleclinic wrote:

are you running the tyres tubeless, if not convert and use 25 psi max. That cures all sort of problems at a stroke.

DavidRadar wrote:

Hello. Okay I Googled your pushbike and found it has XC-2 Rims. I am not sure if I got the correct specs from the giant website but I referenced the 29"

If you do some further research there are maximum and minimum tire width recommended by manufactures of rims. I know mine are DT Swiss and there website states this info. Just having a quick look at I would think 2.4 would be the max recommended for 19mm wide rims. I would take the previous poster advice and go tubeless if not already.


XC-1 is 23mm wide
XC-2 is 19mm wide

Thanks chaps for both of these comments... No I'm not tubeless but it is on my 'to do' list.

The wheels are XC2's but the Giant website states a inner width of 21mm. I have the 2018 27.5 version.

https://www.giant-bicycles.com/gb/fathom-2-2018