Singlespeed & Fixed Gear - Reynolds 520 vs 631

OK I've found a lot of information on the internet about CroMoly. Still, when it comes to track frames, which is the better, the 520, or the 631? Which is stronger, lighter, cheaper, etc?

My understanding is that the Kilo tt is 520, and the IRO is 631. Alot of factors albeit, which one is choice?

Even I have to admit a little searching would answer this right-quick...

631 is the higher grade tubing... 520 is the cheaper; do a google search and you can read to your heart's delight.

I thought the kilo was 4130? Yeah, bikesdirect says 4130 frame and fork...

same diff

is it? serious question. 4130 is same as 520?

i could be making it up but i'm pretty sure i'm not. it's either exactly the same or comparable

is it? serious question. 4130 is same as 520?


Yes. 520 is Reynolds branded 4130.

I have to confess I might've gotten confused by the Bikeisland frames... those are definitely 520.

i could be making it up but i'm pretty sure i'm not. it's either exactly the same or comparable

haha, yeah, you're right, I got unlazy and googled it and there happened to be a thread from the framebuilders forum. case closed.

http://www.bikeforums.net/archive/index.php/t-253635.html

I have to confess I might've gotten confused by the Bikeisland frames... those are definitely 520.

oh alright, the bikeisland site says they are 520, bikesdirect says 4130, being that they are the same alloy I would imagine in the most recent run of kilo frames 520 was cheaper, and became the tubing of choice.

Even I have to admit a little searching would answer this right-quick...

631 is the higher grade tubing... 520 is the cheaper; do a google search and you can read to your heart's delight.

true. i actually found that the 520/4140 is inferior to the 631. i guess i was asking if the difference was worth paying $150 extra. the angus is $150 more than the kilo tt. i've seen kids say get the tt or the iro, but nobody really gives a good explanation of why. i can't find a weight for the kilo anywhere. the iro = 3.9 lb. the steamroller = < 2lb. I'd rather spring for the stronger yet heavier (obviously thicker tubing) iro after reading accounts of cracked steamroller tubing. i'm wondering how well built and how thick the 520 is on the kilo tt. at the moment i'm leaning toward the iro angus. thoughts?

You aren't going to be able to tell a difference between 520 and 631; what you will be able to tell a difference between is the respective geometries of the frames. Pay attention to the geometry of the frames, not the tubing.

true. i actually found that the 520/4140 is inferior to the 631. i guess i was asking if the difference was worth paying $150 extra. the angus is $150 more than the kilo tt. i've seen kids say get the tt or the iro, but nobody really gives a good explanation of why. i can't find a weight for the kilo anywhere. the iro = 3.9 lb. the steamroller = < 2lb. I'd rather spring for the stronger yet heavier (obviously thicker tubing) iro after reading accounts of cracked steamroller tubing. i'm wondering how well built and how thick the 520 is on the kilo tt. at the moment i'm leaning toward the iro angus. thoughts?

As was stated above, look to geometry first. I think you would be hard pressed to crack any of those frames. The kilo is a pretty solid frame, I dont think you would have problems with it.

As was stated above, look to geometry first. I think you would be hard pressed to crack any of those frames. The kilo is a pretty solid frame, I dont think you would have problems with it.

yeah i like that kilo aslso. i've been searching around this forum and can't really find a straight answer as to WHY one of the following frames is the better: kilo tt or iro angus.

Yeah the new kilo's are 520.

yeah i like that kilo aslso. i've been searching around this forum and can't really find a straight answer as to WHY one of the following frames is the better: kilo tt or iro angus.

There is no 'better'. There is only better for you.

In other words, what kind of ride are you looking for? What do you want in a frame? Unless you know this no one can give you any suggestions.

There is no 'better'. There is only better for you.

In other words, what kind of ride are you looking for? What do you want in a frame? Unless you know this no one can give you any suggestions.

ok, currently i am riding a conversion that use to be a cruiser. it's a fun bike. what i'm looking for now is something i can lean forward on and haw some ass in the city. is there really that much of a difference between these two bikes? if so, maybe i need to just stick with my conversion until i know what i really want in a frame as you say. I thought i just wanted something light, that wouldn't break, and is comfortable. apparently theres more to it than that.

I thought i just wanted something light, that wouldn't break, and is comfortable.

I wouldn't worry too much about weight.Any decent 4130 frame will build up light enough for riding around in the city.When it comes to different grades of tubing the difference is often so small that it matters only in competition applications.As for comfort,trackframes are far from "comfortable" in the streets.

Tubing is distinguished by several things: materials, cross-section, butting and wall thickness. That's why different manufacturers sell different tubesets made from the same material but call them "custom butted". Butting a tubeset is not an expensive operation, so customization options exist as different brands like Reynolds, Columbus, Tange even though the all use the same basic 4130 cr-mo stock.

Straight gauge, single-, double-butted or triple-butting is what makes the biggest difference in frame weight. For example, the Kilo TT frame is double-butted, while the Schwinn Madison is straight guage (hence it is much heavier). Not sure, but I think the Pake frame is also single-butted since it also reputed to be on the heavy side (correct me if I'm wrong).

I can't imagine breaking a frame in normal conditions. Trains, Planes, Cars, and Fixed gear skydiving, though.

Straight gauge, single-, double-butted or triple-butting is what makes the biggest difference in frame weight. For example, the Kilo TT frame is double-butted, while the Schwinn Madison is straight guage (hence it is much heavier). Not sure, but I think the Pake frame is also single-butted since it also reputed to be on the heavy side (correct me if I'm wrong).

FYI, the Madison is double butted. (From the Schwinn website: "Schwinn Custom track frame w/ N'Gauged Double Butted Cr-mo main tubes and 6mm thick horizontal dropouts.") I'm also not terribly convinced the frame alone weighs any more than the Kilo TT, at least from my experience with the two. It's more due to some of the crap components that you end up with a heavier build out the box.

Anyway, you're on the money with the butting thing apart from that.

From Reynoldsusa.com,

Reynolds 631 - cold drawn
UTS: 52 - 58 Tsi, 115 - 130 Ksi,
800 - 900 MPa

Following on from the success of 853, Reynolds have added 631 to the range of AIR HARDENING STEEL tube sets. This seamless cold drawn steel tube will allow the benefits of this new steel to be used in the manufacture of a wide range of frames and is now considered a worthy successor to our legendary 531 tubing. Like 853 it is suitable for TIG welding and brazing and in the heat affected joint areas will gain strength, to ultimate tensile strengths in excess of heat treated chrome molybdenum. The strength to weight ratio of 631 is equal to that of many aluminium frames, and it has an excellent fatigue life whilst providing a supple ride quality suitable for long distance events.

On road and touring frames we suggest 631 or 525 forks be used in conjunction with 631 frames. As 631 is only available in main frame tube sizes, we recommend the use of either heat treated CrMo (725) or cold drawn CrMo (525) seatstays and chainstays to complete the frame."

520 is Reynolds 4130. Butted and TIG weldable.

Tubing is distinguished by several things: materials, cross-section, butting and wall thickness. That's why different manufacturers sell different tubesets made from the same material but call them "custom butted". Butting a tubeset is not an expensive operation, so customization options exist as different brands like Reynolds, Columbus, Tange even though the all use the same basic 4130 cr-mo stock.

Straight gauge, single-, double-butted or triple-butting is what makes the biggest difference in frame weight. For example, the Kilo TT frame is double-butted, while the Schwinn Madison is straight guage (hence it is much heavier). Not sure, but I think the Pake frame is also single-butted since it also reputed to be on the heavy side (correct me if I'm wrong).

You seem to use single butted and straight gauge interchangeably. Single butted tubes are also butted, just one end of the tube only. straight gauge as the name implies is just that.

what's the use in making single butted tubes?

^^^seat tubes

You seem to use single butted and straight gauge interchangeably. Single butted tubes are also butted, just one end of the tube only. straight gauge as the name implies is just that.

I know the difference between the two. I meant to say I think the Pake is straight guage as well, sorry (brain fart)... I was wrong about the Schwinn frame though...should have done my homework on that. However, the rest of the post is true in general.

Strong Frames :: Tube Descriptions (http://www.strongframes.com/material_tech/specs/)

unfortunately that doesn't list 520... I'm not sure 525 is the same (I think it may be different, not sure how exactly).

while I don't disagree with Ziemas about geometry, I'll also point out the obvious for the benefit of the OP: the quality of the finished product, beyond the material and geometry, is also affected by the skill of s/he building the frame... how noticeable the difference would be to someone coming from a carbon steel bike, I dunno... but the cheap factory built frames are... well... cheap.

On the otherhand, they're also cheap.

:D

unfortunately that doesn't list 520... I'm not sure 525 is the same (I think it may be different, not sure how exactly).

while I don't disagree with Ziemas about geometry, I'll also point out the obvious for the benefit of the OP: the quality of the finished product, beyond the material and geometry, is also affected by the skill of s/he building the frame... how noticeable the difference would be to someone coming from a carbon steel bike, I dunno... but the cheap factory built frames are... well... cheap.

On the otherhand, they're also cheap.

:D

The OP is looking for an affordable bike, and cheap frames from Taiwan like the ones he mentioned are just fine; there is no reason why he would need a boutique frame.

You aren't going to be able to tell a difference between 520 and 631; what you will be able to tell a difference between is the respective geometries of the frames. Pay attention to the geometry of the frames, not the tubing.

Very true. I have bikes with 4130(IRO), 631(Surly), and 853(custom Steelman). All three ride great because of their geometries, not tubing. The only difference is weight, and less money in your pocket.

The OP is looking for an affordable bike, and cheap frames from Taiwan like the ones he mentioned are just fine; there is no reason why he would need a boutique frame.

I realize... hence the second cheap.

There remains a difference between cheap, moderately priced, and "boutique" as you put it... on the other hand compared to a carbon steel frame, even a factory built frame may be a significant improvement (hence the OP's enjoyment of his friend's Windsor).

I realize... hence the second cheap.

There remains a difference between cheap, moderately priced, and "boutique" as you put it... on the other hand compared to a carbon steel frame, even a factory built frame may be a significant improvement (hence the OP's enjoyment of his friend's Windsor).

You're putting the words "boutique" in my mouth.

What is the functional difference to an inexperienced rider?

increased sense of self-satisfaction

not much of one probably... but as long as we're responding to the OP's question, why not give him information beyond that which he may or may not currently be able to appreciate?

not much of one probably... but as long as we're responding to the OP's question, why not give him information beyond that which he may or may not currently be able to appreciate?

Because it's irrelevant, confusing, and will just muddle the decision making process.

and how will your comments on geometry, without a good deal more explanation, help someone who's likely going to order a bicycle on the internet without test riding different bikes first?

Just remember you have 3 options in frames...stong, light, cheap... but you can only pick 2

and how will your comments on geometry, without a good deal more explanation, help someone who's likely going to order a bicycle on the internet without test riding different bikes first?

It will let him know that he is barking up the wrong tree as far as tubing goes and get him to look into geometry, which is what will really make a difference for him.

After he has done a little research into what geometry will be best for how he would like to ride he can come back and ask more detailed questions.

one can hope!

no offense to OP, but see his earlier thread that preceded this one (as opposed to an earlier thread that came after this one? admittedly makes no sense but presumably you know what I mean: earlier thread).

true. i actually found that the 520/4140 is inferior to the 631. i guess i was asking if the difference was worth paying $150 extra. the angus is $150 more than the kilo tt. i've seen kids say get the tt or the iro, but nobody really gives a good explanation of why. i can't find a weight for the kilo anywhere. the iro = 3.9 lb. the steamroller = < 2lb. I'd rather spring for the stronger yet heavier (obviously thicker tubing) iro after reading accounts of cracked steamroller tubing. i'm wondering how well built and how thick the 520 is on the kilo tt. at the moment i'm leaning toward the iro angus. thoughts?
Look at it this way:
Bikes Direct looked at doing a Platinum EX tubed Kilo frame (exact frame, just a big upgrade in tubing) and a Reynolds 853 (huge upgrade from 520). They found that the Platinum EX tubed frameset was 70 grams lighter, and the 853 was something like 85. So weight difference on a tig welded frame isn't going to be huge. There will be an upgrade in ride quality which may or may not be detectable to you. Unless IRO did another group buy the Kilo TT is hands down the best deal out on a new frameset.

In comparing IRO to Kilo TT in respects to build quality both are on the lower end. Every IRO group buy frame I saw on a frame jig was off by a bit. I've seen 1 Kilo TT on a frame jig and it was off as well. The welds I've seen on both are pretty standard grade mass produced TIG. Would you get that with a $500 FSB Sword? I doubt it as the two I have seen were pretty good from the factory. You would not see those kind of imperfections on a $1000 Gunnar, but you are looking at sub $350 framesets so people need to be realistic in their discussion.

It will let him know that he is barking up the wrong tree as far as tubing goes and get him to look into geometry, which is what will really make a difference for him.

After he has done a little research into what geometry will be best for how he would like to ride he can come back and ask more detailed questions.

I'll do some geometry research and see where I end up...

one can hope!

no offense to OP, but see his earlier thread that preceded this one (as opposed to an earlier thread that came after this one? admittedly makes no sense but presumably you know what I mean: earlier thread).

Not really sure what you're talking about, but you're probably right. No offense taken, I'm learning and that's my goal.

There will be an upgrade in ride quality which may or may not be detectable to you. Unless IRO did another group buy the Kilo TT is hands down the best deal out on a new frameset.

I have to say, I don't think that an upgrade in tubing makes a big difference in ride quality, based on my experience. My straight-gauge 4130 IRO and my CroMo-to-HiTen Trek were probably my two "best riding" bikes I've ever owned, as I've owned lots. I think it had everything to do with the geometry, and next to nothing to do with the steel.