Fixed Gear tires, tubes, and rims size Question.
 

Hey guys, my fixie has a 30mm deep-V rim (not sure what it means, please explain), and it has 700cx23 (26inch)
tires. I'm considering on changing it to a slightly wider tire. 700cx25, but I'm not sure how to choose the one that is compatible. If you can please explain to me what I should look for so that the new rims and tires are compatible with my fork. Thank you.

Another thing, what do I look for if I want to change my chains to a bigger ratio? What is ratio and how does it affect one's ability to skid easier? Thank you!

Are you getting new wheels or just new tires on your current rims? 30mm is the depth of the rim (spoke hole to edge of the rim where the tire starts). If you have 700x23 tires on there now you probably can run the 25's. That number is referring to the width of the tire in mm on a certain rim. It could be slightly narrower or wider on your particular rim depending on the actual rim width. How close is your current tire to rubbing on the frame? Could a slightly wider (25) fit?

How many teeth are on your front chain wheel and your rear cog? More teeth in the front will make for a bigger gear (slower pedaling for the same speed). More teeth in the back make for a smaller gear (faster pedaling for the same speed).

I have no idea about skidding because I've never done it and have no desire to do it. I do know that certain ratios cause you to skid at the same spot on the tire which should be avoided.

Note well that 700c and 26" are two different rim sizes and one won't fit on the other. 26" wheels are cruiser and MTB wheels, usually. See http://www.sheldonbrown.com/tire-sizing.html

I am going to guess that you have 700c wheels. That's the diameter.

As for going with a tire of greater width, that's a different question and whether it fits or not depends on the clearance at the fork (front wheel) and brake bridge and chainstays (rear wheel). Unless it's a true track bike, I would think a 25mm tire will fit, but you'll have to check. How much clearance do you have now?

25c is not very noticeable IMO, look at 28c and just take it to a bike shop and ask if you can check if it will fit. or easier yet, measure your tire clearance, there are only 3 places to measure - front fork, rear seat stays and chainstays. 28c tires tend to be about an inch wide. keep in mind however you'll need to have clearance radially too (how much the diameter is actually increased with the new tire)

Definitely get some 26"x25c for the smallest ratio for easier skids. Change your front and back chains to match.

Outside diameter of a 700x23 is about 26.5", but it's not a 26" tire or rim.

I wouldn't change tires 'til wearing out the current ones.

You gotta see what will fit. I've only had one bike that wouldn't fit 25s, but you still wanna check and make sure.

in terms of skid stopping, gear ratios make more sense in terms of leverage: if you have a 14t cog on your wheel and a 52t chainring, your cranks would probably have enough leverage to break bones without even going too fast. closer to equal teeth makes pedaling, and backpedaling easier. so you can get a BIGGER cog or SMALLER chainring. chainring will be easiest to change out, though there are a few different BCD sizes.

the ratio is how many times the wheel rotates when the cranks make a full rotation. 14x52 would be almost 4:1, most people who ride fixed like it between 2 and 3

no joke tho, 26" is a hell of a lot easier to push than 700s with the same ratio

That's because gear ratios are worthless and gear inches are what matters.

Unless you're rollin' 26x2.35", then it's about the same as 700x23.

But yeah, point still holds if you go with smaller 26" tires of the 559 BSD variety.

I much prefer talking about gear inches rather than ratios. 75 gear inches on a 700 wheel is the same as 75 gear inches on a 20". Easier to compare from a common point of reference.

well as far as ratios go, a lower ratio will let you skid easier but you will end up spinning alot and not really going anywhere. I currently ride a 56:12 and it is almost impossible for me to skid. i rarely do skid though. It wears down your tires unless you have a decent back tire. like the freedom thick slick. my commuter is a 44:15.very easy to skid and not too spinny. google a skid patch chart. a skid patch is a spot that you will always skid on. certain ratios allow you to have up to 18 skid patches. you can however rotate your tire on the rim itself to avoid having like one skid patch. thats really annoying and youll always feel this little bump when you ride if you only have one skid patch and dont rotate the tire. something that would be good for a novice like yourself would be a 48:17. its low in gear inches (which means means its easier to pedal and easier to skid) and the 17 tooth cog will give you 17 skid patches. with tires i would stick with 700cx25. its the best width in my experience. 23's wont hold up as well if you hit a bump and the tire will not protect the rim and youll end up denting your rim. anything above a 25 is more for like hybrid commuter bikes. so id say stick with a 700cX25. if youre going to buy a chain. go kmc brand. always hold up great. cheers. and happy riding.

56x12 on a 700 - 25mm tire is 123 gear inches.

That's my granny gear.

Down a 20% hill, sure...

I was hoping that was a typo. Even a 46/12 is around 100". Who really rides around in that big a gear?

Not being able to skid equals not being able to stop in an emergency. Funny I run 23's and have no issues with wrecking rims because of it.

well i am a little on the heavy side. i weigh about 205 lbs. so that might be a factor. i personally have dented rims like that. just by hitting a small bump. like those reflectors in the road. but like i said it probably because im fat. lol.

its a good ratio. a little difficult at first but you get used to it. its pretty much flat where i live. so i dont ever deal with hills. :/ i wish there were hills.

Hey, this is the details about the bike. I'm not sure how much clearance I have, but my current 700cx23 seems to have a a centimeter before it touches the dome of the brake bridge, and about half a cm between the brake. This is the full detail of the bike
Critical Cycles Fixed-Gear / Single-Speed Bikes with Pista Handlebars | With Flip-Flop
Thank you!

Hi thank you for replying, Ièm not sure about the rims because the description listing only says 30mm deop v double wall rims. Here's the full description of the parts that I have on my bike.
Critical Cycles Fixed-Gear / Single-Speed Bikes with Pista Handlebars | With Flip-Flop

Hi, thank you for replying. This is the full detail of the bike
Critical Cycles Fixed-Gear / Single-Speed Bikes with Pista Handlebars | With Flip-Flop

I'm still not sure since in the listing the size of the chain only lists as KMC 1/8", not sure what that means.

Don't worry about the chain size..that's irrelevant to gearing. Chains come in two widths...3/32nd and 1/8th. With a 1/8th chain, you can run both 3/32nd and 1/8th chainrings and rear cogs. If you had a 3/32 chain, you would only be able to run 3/32 chainring and cogs.

Cog = small toothed wheel that sits on the back hub.
Chainring = big toothed wheel that sits on the crank arms.

Changing your rear cog to just 1-2 teeth can make a significant difference (like a 14t to a 16t). Now if you change your front chainring just 1-2 teeth, it's a much less significant difference. I forgot the actual number but for every change in ONE tooth on the rear cog (like 14t to 15t) is similar to changing THREE teeth on the chainring (like 45t to 48t).
Take a look at this chart...it will make more sense.
http://www.bikeforums.net/singlespee...ng-primer.html

On the street, most people run between a 65-75 gear inches depending on your hills. I'm in Seattle and run around a mid 60.

On the product page, it says your bike has a 16t rear cog. Not sure about the front. All you need to do is look at the front chainring (the gear around your cranks) and simply count the teeth.

If it's a 45, your gearing will be 45x16
If it's a 47, your gearing will be 47x16

You can then look at the chart to find out your gear inches. Most likely it will be in the 68-72 range.

If so, you should be able to fit 25mm tires.