ATX_McKee

Hi everybody, I'm a new user here. I just bought my first bike since my old BMX days in middle school. It's a Critical Cycles fixie, but I'm using the freewheel. I have never ridden a road bike, and my biggest concern is the tires. Like I said, I haven't ridden since middle school, and that was on 20" BMX bikes with fat tires that could hold up to abuse. I'm right around 250 lbs, not sure exactly, and I'm just worried about the tires not being able to handle that much weight.

I guess really I just want someone with experience to tell me it's fine and that I'm not going to bust my face when a tire blows. Or tell me that that's totally going to happen and I'm an idiot for buying a road bike. Either way I'll feel better.

PS: I've been stalking this site for a while now so I've picked up on a few things. No, my bike is not a Kilo TT. I'm a poor college student, leave me alone.

Huffandstuff

Just don't hop curbs and avoid potholes/lift your ass if you are gonna hit one.

You could also throw some 28 or 32c tires just for added measure(if you don't already have them).

highonpez

Keep 'em pumped up properly and you'll be fine. Also, a little wider couldn't hurt and would make the ride more comfy for you. If your tube does pop you won't fly, you'll just slow down quickly until you realize there's no air in the tire.

Jaytron

You'll be fine, just check your psi before each ride.

ATX_McKee

I appreciate the replies. It really does help my confidence. I should have clarified the current tires it came with are 700x23c. If I went up to a 32 would I also have to replace the rims? I'm pretty much strapped for cash until my school loans come in. I actually sold my computer to buy this bike (determined to lose weight, dammit!)

Jaytron

You won't have to replace your rims, just make sure the bike has enough clearance.

I prefer 25c tbh. 23c is fine if cash is tight, just watch your psi. Good luck dropping weight. I was 235 when I started and got as low as 179

ATX_McKee

Thanks. Cycling is really the only exercise I've ever enjoyed other than swimming, and my apartment pool is too short for decent laps. I'll check out some bigger tires, any particular brands to look at?

hairnet

Panaracer is good for quality and fair cost. It's not clear what tire size your bike clear but if this means anything then 28mm tires shouldnt be a problem, 32mm is a possibility.

ATX_McKee

Yeah I'm becoming very annoyed with Critical Cycles for not offering proper specs. I'll likely just take it to a shop and get some first hand help as far as clearance.

Scrodzilla

I recently put a set of 28c tires on a Critical for a customer at the shop. Plenty of clearance.

ATX_McKee

Yeah I was in bed when I said I would need to check the clearance. Just looked and there's plenty of space there. I think I'm going to stick to the 23s for now and try to gain some confidence on them. If my school loans come in and I'm still having trouble I'll bump them up. Thanks again everybody.

JeremyLC

23mm tires should be fine. I was ~250Lbs when I started commuting on a bike with 23mm tires and I didn't have trouble with flats other than road debris. Keep your tires inflated well and they should be fine. Keep riding (and watching your diet) and the weight will come off. (I'm down to about 150Lbs now :-))

TejanoTrackie 

OP - you find this tire pressure .vs. tire size and rider weight helpful:

Tire Width=20: Pressure(psi) = (0.33 * Rider Weight in lbs) + 63.33
Tire Width=23: Pressure(psi) = (0.33 * Rider Weight in lbs) + 53.33
Tire Width=25: Pressure(psi) = (0.33 * Rider Weight in lbs) + 43.33
Tire Width=28: Pressure(psi) = (0.33 * Rider Weight in lbs) + 33.33
Tire Width=32: Pressure(psi) = (0.17 * Rider Weight in lbs) + 41.67
Tire Width=37: Pressure(psi) = (0.17 * Rider Weight in lbs) + 26.67

Front Pressure = .9*Rear Pressure

So in your case rear tire pressure = (.33 x 250 lbs) + 53.33 = 82.5 + 53.33 = 136 psi, which is probably way more than your tires or rims can handle. Front tire pressure = .9 x 136 psi = 122 psi, which is borderline high, depending on the quality of the tire. Therefore, I'd recommend going with 32mm rear and 28mm front, and inflating them to (.17 x 250 lbs) + 41.67 = 84 psi rear and .9 x [(.33 x 250 lbs) + 33.33 psi] = 104 psi front. Those are approximate numbers of course, but most tires these sizes can handle those pressures.

ATX_McKee

Is there any noticeable change in handling having different size tires on the front and back? That's interesting I'd never heard of that before.

TejanoTrackie 

Actually, steering and handling is better with a narrower tire up front than in back. There is more weight over the rear wheel than the front, so if you use the same size tires front and rear, you need much higher pressure in the rear than the front. If your rear pressure is too low, you risk a pinch flat. If your front pressure is too high, your ride will be harsh. Also, the rear tire will wear out much quicker than the front if they are the same size. Many of my bikes are set up with a wider tire in the rear than the front. However, the difference is only one size, such as 23/25, 28/32 and 32/35. Most motorcycles are set up this way with a wider tire in the rear than in the front.

ATX_McKee

Spinoff question. Will bigger tires give me a little more cushion? The sidewalks and roads here are kinda rough, and my a$$ is taking a beating. Granted, I also need a better seat.

TejanoTrackie 

Absolutely. That's why a lot of urban and touring bikes feature fatter tires which can be run at lower pressures to help soak up the bumps w/o significantly increasing rolling resistance. In fact, I just bought a new geared road bike that comes with 700c x 28 tires, and it's a much nicer ride on the Texas chip seal roads. I'm able to run 75 psi front and 85 psi rear with them w/o any risk of pinch flats when I go fast over bad railroad crossings and hit potholes. Of course, I only weigh 140 lbs, so that's plenty of pressure for that size tire.

hairnet

They will. 28s are nice when the bike is unloaded but at my weight(200lbs) + gear the ride can sometimes still be rough. 35s are pretty smooth but sluggish and I have yet to try out 32mm tires. Of course tire makes also makes a huge difference.

ATX_McKee

Cool. I think I'm gonna get 32s. Not too worried about the sluggishness, I don't need speed as much as comfort.

europa

Mate, there's no need to change your tyres until they wear out - actually, it'll be the rear one that wears out first. Nothing stopping you changing now of course, but if money is an issue, wear the current ones out first. Whatever you do, don't rush into it, research your options and be aware that shops, both online AND bricks and mortar, have specials, sometimes very good specials just be patient and keep your eyes open.

The physical size of the tyre will vary from manufacturer to manufacturer - a 25mm tyre in one brand/model will be fatter than a 25mm tyre in another.
You will run out of clearance on your frame very quickly. I don't know your bike but it may not like 32mm tyres, the only way to test this is to try it. It's useful knowing someone with the same bike who has done the experiments or someone with fatter tyres who is willing to try his wheels in your bike.

ATX_McKee

I've been riding the 23s for a few days now and they're growing on me. I'm nervous about a lot of things in general, so hopping back on a bike has been difficult. A couple of car crashes really messed up my psyche. But I'm getting more confident so we'll see what happens. I'm not rushing out to buy anything right now, I'm flat broke until school loans come in.

I am having one new issue though. I filled the tires with a compressor and was able to get them to 60psi. The tires don't have a range on the side, they just say fill to 100psi. But they already feel super stiff. Can I just leave them as is? The ride is pretty comfortable so if I don't have to add more air I'd rather not.

Notgrownup

I havew 32c on my quick and i am 245lbs... at 85PSI thye are kind of hard but roll good. I would ride those 23c until they burst or wear out just a little pressure tweaking and you will be fine...Fine as frog hair split 4 ways...

seau grateau

The problem with running skinny tires at low PSI is that you become much more prone to pinch flats, which are a huge pain and often impossible to patch. Fill them to the recommended pressure. It may feel a little more harsh, but you'll save yourself a lot of tubes.

hairnet

Before you buy new tires buy yourself a floor pump.

TejanoTrackie 

You can't judge tires by how they feel. Skinny tires inflated to 60 psi feel about the same as they do inflated to 100 psi. At your weight, you won't get very far with 60 psi in a 23mm rear tire before you get a pinch flat.