Fat bloke with questions!

ipdaly

Morning all, my first post...

Being 20 stone i thought it was time i started doing stuff i loved when i was a kid, Rugby and Biking

Picked up a Giant Yukon and so far think its a great bit of kit, only using it on roads/canal paths etc but it has been perfect. I wanted to know what sort of psi i should run? It has Continental Mountain Kings 2.2 fitted and at some point i will be fitting less "off road" tyres, it has the presta valve and i was told the wheels wont allow for the car type valve to be fitted, is that true?
Thanks for reading and all responses will be very welcome!

Giraffoto

Good morning and welcome to the forum. To tackle the last bit of your post first, the type of valve is not relevant to how much pressure you can get in the tyre. With either Schraeder or Presta valves you can get enough air in there to blow the tyre off the rim with a hand pump (don't try this at home, particularly indoors). Presta valves have the advantage of being easier to let air out of if you ride on the road for a bit and then want to go off-road, and if you have a thin-wheeled bike you only need one pump fitting. There may be other advantages too.
Next: what pressure? Very variable, a lot of it comes down to preferences and how you ride, but a good rule of thumb is to have enough pressure to keep the tyre from looking like it's going flat when you're sat on it. This can be tricky to judge from above, so it may be helpful to have someone else looking at the tyres while you try different pressures.
And get a track pump - you'll wonder how you ever did without one.

ElliesDad

+1 for the track pump!

I am a "bigger" bloke as well and have recently dropped from 17.5 stone to just over 16 stone in a couple of months just by taking up cycling. I have Panaracer Fire XC Pros on my bike which I run at 55psi for cycle path and road work which I drop to 35psi for trails for more grip.

As far as changing the tyres go, if like me you start thinking you will only cycle on paths/road sooner or later you will probably be bitten by the bug as your confidence and fitness improve and you will want to tackle more challenging stuff like red routes. If this is the case consider changing to something like Fire XC Pros which offer good performance on road (when pumped up!) but also offer a fair amount of grip on trails. I had the MK 2.2 tyres before I changed to the Panaracers and to be honest found the Mountain Kings terrible when the going got a bit muddy, even on cycle paths!

mountaingoatimnot

There is no easy answer to the pressures question - it depends somewhat on the size of the tyre you have fitted (2.35/2.4" tyres allowing for a little less air than the smaller 2.0/2.1 tyres).

When riding off-road you really want to avoid pinch / snake bite punctures, caused by underinflation and the rim pinching the edge/sidewall of the tyres. Whilst general advice is for maybe less pressure when off-road, this does depend on rider weight and tyre volume.

I'd suggest you start at 40psi and see how the tyre looks when you sit on the bike - you may have to go a little higher with smaller tyres but i wouldn't go above 45psi unless you really have to due to deformation.

The hardtial Yukons came with 1.95/2.0" tyres from recollection, the full suspension variants with bigger 2.1". If you have the former don;t be alarmed if you have to go to 45psi given your current weight

oxocube1

Have a look at the tyres you have and check the sidewalls. Almost every tyre will give a range in PSI and Bar for the suggested minimum and maximum pressures. I would not advise to pump them up to the absolute max, but as you are a little heavier than me for example, you would have to pump them maybe 5-10 psi less than the max. To quote Sheldon Brown:

"A tire is supposed to deflect a bit under load. This deflection the whole purpose of pneumatic tires. When you sit on your bike, your tires should visibly bulge out at least a bit under your weight. If they don't, they're overinflated."

Have a read of this article he wrote: http://www.sheldonbrown.com/tires.html

Explains everything you need to know plus a lot more info!

supersonic

You can buy adaptors for presta valves to make them car valves.

1mancity2

ipdaly wrote:

Morning all, my first post...

Being 20 stone i thought it was time i started doing stuff i loved when i was a kid, Rugby and Biking

Picked up a Giant Yukon and so far think its a great bit of kit, only using it on roads/canal paths etc but it has been perfect. I wanted to know what sort of psi i should run? It has Continental Mountain Kings 2.2 fitted and at some point i will be fitting less "off road" tyres, it has the presta valve and i was told the wheels wont allow for the car type valve to be fitted, is that true?

Thanks for reading and all responses will be very welcome!

Some rims are made for presta value and the valve hole is smaller and won't allow a "car valve" if this is the case with your rims you can drill the hole so it accepts the bigger valve, just make sure you deburr it well after.

ipdaly

Thanks for all the posts, much appreciated!

My bike is a hardtail. The tyres state they can hold 65psi. I am picking up a presta pump (track as advised) with a gauge as was warned off the presta adaptors by a friend.

Another question i wanted to ask is can anyone recommend the slime iner tubes? They seem to get better reviews than the puncture resistant tyres on sale.
Thanks again for the advice.

cooldad

Slime inner tubes are rubbish - heavy and not much use - avoid.

ipdaly

cooldad wrote:

Slime inner tubes are rubbish - heavy and not much use - avoid.

Will look for a decent set of tyres, couldnt see how the slime tubes would be any good, the reviews all seem to be magazines and not actual people! Thanks for the reply.

jayson

cooldad wrote:

Slime inner tubes are rubbish - heavy and not much use - avoid.

I would disagree, i use Dr Sludge tubes on my HT work bike cause i was sick to the back teeth with getting punctures every week and in the couple years ive had them fitted ive had zero punctures.

I ran over a tumb tack one night without realising it and didnt see it until the next morning, i pulled the tack out and topped the air up (it wasnt completely flat like normal) and its been perfect since.

I would hugely recommend them myself.

cooldad

You are quite at liberty to disagree. You're wrong, but you may disagree.
However I don't really ride canals or roads so they might be OK if you're regularly riding over syringes etc.

ipdaly

jayson wrote:

cooldad wrote:

Slime inner tubes are rubbish - heavy and not much use - avoid.

I would disagree, i use Dr Sludge tubes on my HT work bike cause i was sick to the back teeth with getting punctures every week and in the couple years ive had them fitted ive had zero punctures.

I ran over a tumb tack one night without realising it and didnt see it until the next morning, i pulled the tack out and topped the air up (it wasnt completely flat like normal) and its been perfect since.

I would hugely recommend them myself.

Thanks for the comment. Are the Dr Sludge tubes the same as the Slime ones? I take it if you were to get a thorn in the tyre and remove it the liquid would be forced in the hole? Can these work with the "puncture resistant tyres"?
Thanks again for comment.

Roostoids

I use slime tubes on my mtb. ive used dr sludge, slime, and other shop ones of a similar nature.

Cooldad is right to say they are heavy, and they do reduce the roll of your wheels, however since fitting them i haven't had a single puncture in 2 years.

I used a spare set of wheels with normal inner tubes a few months ago, riding on the same trails and got 2 punctures in one ride...coincidence? Maybe. But i always use slime tubes now. spare wheels or not. punctures suck, so id rather pay a bit more and suffer less of them.

Also (no offence) you're 20 stone so do you really care about a few grams in your inner tube?!!

ipdaly

Roostoids wrote:

I use slime tubes on my mtb. ive used dr sludge, slime, and other shop ones of a similar nature.

Cooldad is right to say they are heavy, and they do reduce the roll of your wheels, however since fitting them i haven't had a single puncture in 2 years.

I used a spare set of wheels with normal inner tubes a few months ago, riding on the same trails and got 2 punctures in one ride...coincidence? Maybe. But i always use slime tubes now. spare wheels or not. punctures suck, so id rather pay a bit more and suffer less of them.

Also (no offence) you're 20 stone so do you really care about a few grams in your inner tube?!!

Thanks for the coment. I was unsure whether they actually work, as I said all the reviews seem to be magazines not actual people.
Where did I say I was worried about the weight of the tubes?

Roostoids

Dont think you did but i thought i saw other people discrediting them based on that. For a racer or smaller person perhaps its more relevant but for me at 17stone a few grams here and there on components its irrelevant 8)

Dandelionclock30

I dont think the slime tubes are very good either,I had punctures with them as they dont cope with a big puncture like a gash. I was getting quite a lot of punctures at one point and instead got some better tyres which were more puncture resistant. This is a better option in my opinion.
Also you can get better inner tubes.

cooldad

Problem is not a little bit of weight, it's where it is.

YeehaaMcgee

Roostoids wrote:

Also (no offence) you're 20 stone so do you really care about a few grams in your inner tube?!!

Every little helps when you're still building up your fitness. A featherweight racing snake will have enough power and endurance to just ride on anwyay. Might not be the case when you're struggling to get a handful of miles in

Roostoids

Could be you're right Yeeha. I can only speak for myself and my own experience, and I just feel like when i'm carrying round excess weight on my 'relaxed waist' there's little point me worrying about a small weight penalty on inner tubes, especially as they reduce the number of punctures suffered, which I think is a big + !

Besides, pedalling a heavier bike will make a person work harder, and put them in the fat burning zone sooner, just gotta hope it doesnt push them up and out of that threshold 8)

I suppose an even better option is completely tubeles? But I've no experience with that.

The Rookie

Don't get the cheap Halfords one, one of the guys in the club did, one thorn later and the ony difference was a tyre full of white muck it took an age to get clean enough to re-use!

Dr Slime are better than that at least!

Personally I use normal tubes so can't really comment beyond that.