Now, I’m a rather large 126kg (277lb) bloke attempting to use a racing-style bike as a daily commuter (until I can buy an MTB or tourer). The bike was given to me by my dad, and the brand is unknown. He was given it second-hand. It’s a cheapie by the look of it. The tires are unbranded, and there is no recommended pressure indicated on the side wall.
I’m about to go to the gas station and pump in some air. Remembering I’m a big guy, and the tires are unbranded…
Most bike tyres can take 60 PSI (4 bar) - try that for the rear tyre, and see how it looks. If it feels too hard, let some air out; if the tyre squashes too much under load, put some more air in. It’s a compromise - higher pressure = low rolling resistance and the ability to maintain shape under cornering loads, low pressure = better grip, more comfortable, but a little squirmy under cornering loads.
Use a little less pressure in the front tyre as there’s less load on it - about 40 PSI should do it. Ultimately it’s all a matter of feel, and you can adjust the pressures (within upper and lower limits) to suit your requirements.
If I had to make a call on this particular bike, I’d inflate the tyres a little less than I’d normally like, just to get a bit of extra grip. Cheap tyres are rubbish when they’re new, and only degrade with age. Rub your finger along the rubber, and it should feel a little squeaky. If it doesn’t, then you may expect the bike to shoot away from underneath you on a wet corner one day.
Oh yeah, and careful of inflating bicycle tyres on a gas station air compressor. They’re designed for the much higher volumes of car tyres, and can inflate a bicycle tyre to bursting point in a fraction of a second.
The only alternative to the gas station in the immediate short term, is the pump that came with the bike. It looks almost like a child’s toy, and seems to leak air faster than I can pump it into the tire. I’ll try my luck with the automotive pump.
This guy has a neat little table of recommendations for tyre width/weight/pressure settings, if you trust him
Speaking as a 70kg chick on a hybrid, my tyres say 75psi, which I find uncomfortably tight, and they can go VERY low before I start thinking “hmm…time for some air” (last time, after an admitted many-months-long cycling rest, I got all the way down to the city and back on 8psi before I finally bothered ducking into the servo next to my house. You’d probably notice something wrong a little bit sooner…)
WAG … try something on the low side, maybe 50 or 60, then ride it round and see how it feels.
Odd that the tires don’t have the pressure embossed.
I have a Specialized Allez, a road bike. Its tires take 110 lbs. 60 lbs sounds too low for a “racing” bike.
The advice to watch out for the pump at the gas station is very good, although you might get away with short bursts. When properly filled the tire should feel hard when you squeeze it. When you get on the bike you should not see the tire flatten out noticeably.
If you’re going to get another bike anyway, consider getting a decent hand pump. They’re not terribly expensive.
Given that Sydney is a hilly, car-oriented city, I am blessed with my commute. I have about six or seven kilometres of nearly flat route comprised of about 85% dedicated cycleway and the other 15% quiet residential streets.
I’m overweight and out of condition, and my aim is to have an easy, slow trip to work, rather than a sweaty, lycra-clad record-breaking sprint. I just want a cruisy alternative commuting method that can save me some time and money, and possibly help me get fit in the process.
If you are serious about cycling long term then get yourself a Track Pump. They don’t have to be very expensive and they are the easiest way to keep your tires up to pressure. Most models will fit all types of bike tire valve.
For a road bike (racing style) bioke I think you will find 60 PSI to be low. For a person of your size (I am close to that weight myself) 100-110 PSI is probably closer tot he mark.
As is mentioned in Aspidistra’s link an under inflated tire is prone to pinch flats and has more rolling resistance.
If you are going to ride to work I would suggest that you get a small under seat bag and carry a spare tube, some tire spoons, and either a CO2 inflator or a pump. Otherwise when you get a flat, you will be walking to work which really sucks.
The OP is talking about a MTB though. Wider tires can’t take high pressure because for a given pressure, wider tires are under more stress, and put more stress on the rims. I wouldn’t put more than 65psi into an MTB tire of unknown rating.
On the other hand, *under-*inflation can cause the tire to be pinched and cause a flat, as already pointed out. For normal city/street use I always inflate my tires to the maximum rated pressure to minimize the chance of pinch flats.
I highly recommend the Topeak Road Morph pump. It has a built-in gauge, and it has a hose so you can use it like a floor pump. (Most portable pumps don’t have a hose, so you need to connect the pump body to the valve. It’s very easy to damage the valve while pumping.)
I just took the bike to the gas station and put 60-ish psi in the front and 85 in the back. The last time I rode a racing bike was when I was a teenager about twenty years ago, and I remember those tires were to be inflated to 90psi, so I hit 85 assuming these things wouldn’t burst. Generally, I like my tires to be a little on the hard side. I’m not pushing the bike to the limits of its grip, and I’m more concerned with rolling resistance than with a smooth ride.
All I can say is that I haven’t been on a bike at all for a few years, and my last one was an MTB. This racing bike feels like it’s not there at all. It’s almost scary. I feel quite vulnerable on it. I’m sure I’ll get used to it though.
Congratulations! That’s one more of us, and one less of them!
Below are a few personal preferences and opinions, others will do things differently. But it’s food for thought, at least.
At some point you’re going to get a puncture, especially with racing tyres. I recommend carrying a small pump with you all the time you ride - the little “shorty” pumps are very compact. It’s easier to get to work with a slow puncture, topping your air off every five minutes, than it is to walk the thing to where you want to go. A decent lock also gives you the option of chaining up, taking the bus and dealing with it later.
Personally I’m very much into the utility and freedom of cycling, so I ride a hybrid with normal pedals and a full-length chainguard. Any clothes, any shoes, no lycra required! But there’s a D-lock on the bike itself, and my two biking bags each contain a pump, puncture repair stuff, lights and waterproofs full time. Gives you more options, and they fit into a bum bag. (You don’t want to have to go home early because it’s getting dark, and you don’t want to cycle at night without lights. Really.)
I’ve also replaced everything “quick release” with their “needs a tool” equivalent. Saving thirty seconds twice a year to take a wheel off stacks up poorly against wasting thirty seconds twice a day locking all the detachable parts together.
As for the OP - I’ve never measured tyre pressure, or even known what it’s meant to be! I use an empirical correletion between the “thumb test” and subjective rolling resistance. But then I’ve never ridden on racing tyres, where I guess it’s more critical.
Definitely going to have to get a new bike soon. This one’s way too small, and I am most decidely not a fan of the racing bike style. I’m sore all over - not so much sore in a “first exercise for ages” way, but in a “that bike doesn’t fit me, and the saddle and handlebars are awful” sort of way.
Still, it was fun, it’s half an hour quicker than the train (more direct route), and I’ve saved myself the fare.
I’m not actually a cycling n00b, so I carry - and know how to use - a puncture repair kit, and an Allen key/spanner/lever tool.
I’m definitely going to find myself a cruisy sort of bike. Lots of lovely low gears, a chain guard, a generous parcel rack, and a comfy saddle.
this doesn’t warrant it’s own thread, so I thought I’d just ask here -
So is it ‘tyres’ or ‘tires’ for Australians? At fist I saw The Loaded Dog’s posts and thought to myself ‘Aha! at least when it comes to spelling ‘tire’, the Aussies are like us!’, then I saw Aspidistra’s post and got all confused…
I don’t normally translate for the 'merkins, but I was just after a quick reply, so I did in that OP, so I kept it up. For the record, I say “tyres” and “petrol station”.
Eek! I’m totally anal about all the tyre pressures in all my vehicles. I can notice a 3 PSI difference between the front tyres in my car, and I tune the pressure in my mountain bike tyres according to the conditions and my mood on the day. For grip under slippy conditions I like 35 PSI in the rear tyre, 28 PSI in the front, and in dry summer hardpack I may go up to 38/30 PSI rear/front as long as I don’t mind the handling being a tad skittish.
I wouldn’t recommend anything above 60 PSI for unmarked road tyres. A proper racing bike will have tyres that will handle high pressures, and in my keen youth I used to ride tubs pumped up to 115PSI. It was within the ratings, yet I never had a tub die a natural death - they either exploded, or ripped themselves apart somehow. But no-name tyres won’t be rated to anything near this. It’s unusual for the pressure ratings not to be marked on the sidewalls though.
TLD if you’re looking for a bike that’s comfortable on the street, I wouldn’t recommend a mountain bike. A full suspension bike will be heavy and slow, and a no suspension bike will rattle your bones. Mountain bike frames have very little give in them, and you don’t get the shock-absorbing ability of a decent road frame. Ideally you want a city bike, which looks like a cross between a mountain bike and a tourer, except with a small amount of front suspension. Some have a little travel in a rear suspension arrangmement too which helps make for a smoother ride without loosing too much pedalling energy.
