Singlespeed & Fixed Gear - Some vs Tange fork???

So I've been looking at getting a new frameset. My current frameset is an IRO angus. It's just not aggressive enough for me.

So I've been looking at getting a Soma Rush. Because it does not come with a fork, I could possibly get something other than the Soma fork. Here's what I've found:

Soma Track fork: 38mm rake.....Tange Infinity tubing
Tange Prestige Fixie fork: 38mm rake.....Tange Prestige tubing
Suggest something better if you know something. But I am afraid of changing the geometry too much with a fork with different rake.

I've read that the infinity tubing is more like Reynolds 520 (double butted CrMo), and Prestige is more like somewhere inbetween Reynolds 631 and 853.

They are close to the same price. So would I just be best suited to go with the Tange Prestige fork? Or is there some reason that Soma went with Infinity tubing (softer front end for plushness perhaps)?

Also.....I know the Rush is not true track geometry with a fork with 38mm rake. But can anyone tell me how much more agile, responsive, and stiff the Rush will be than the IRO angus? Also, I'm weary of the fact that the "rear end" is just double butted CrMo. Anyone want to comment on this?

If the two forks are close to the same price why would you go for the lesser of the two?

Infinity is a less expensive tubing only because it's seamed. In a fork the two different steels will most likely feel identical. I'd go with the prestige though simply because one less fault to occur...prestige's seam cannot fail (it doesn't have a seam!)...not that I've ever heard of such thing. The prestige MIGHT weigh a tiny bit less...stronger tubing=less metal. FWIW I prefer Infinity tubing on my bikes...but I have found GREAT success with straight up 4130 cromo forks. I bought one on Ebay recently for $80 that saved a frame from doom...it shimmied so badly at 23mph+ that I nearly scrapped the project. It was the Tange fork! Also straight bladed forks tend to be all around better than the old curved legged ones in my experience. I've had success with the curved type but NEVER had a single problem with the straight legged variety.

Prestige is a way higher grade of tubing. That's pretty much the long and short of it.

So it's a no brainer and I should definately go with the prestige fork.

Now, does anyone have any input about how ride quality is going to change with the Soma compared to my current IRO?

probably won't be that different. BTW, get a carbon fiber fork.



Rush is a good frame, but so is an Angus. You are giving up Reynolds 631 tubing for the same type of tubing. What size would you be getting?



http://www.irocycle.com/frame_specifications.pdf



http://www.somafab.com/geometry03.html



Looks like the Rush is a bit more track, but I don't know if it will be that drastic of a change for you. The geometry is really the only difference, also. I mean they both have the same tubing (more or less).



Is this bike gonna be used on the track? If not, I don't see the point in this purchase.Why isn't the Angus agressive enough for you? Not twitchy enouguh? Not uncomfortable enough? IMO, there is absolutely no reason why someone needs agressive geo. on the street. I


If you are dead set on track geometry, you might consider the Pista. It's hard to use the Bianchi geometry table, but I have heard that the Pista has very track geometry.



BTW, get a carbon fiber fork.

I'm really needing a smidge bigger frame as well. Probably going to get the 57cm size (measured c-top of seat collar). That's why I was thinking about getting a new frame to begin with, an dI thought it might be fun to try something new out.

Just trying not to downgrade as far as tubing goes I suppose. I really like the ride of the R631 on the IRO.

Just time for something else I suppose.



And I don't want a pista. I'm sticking with steel, and it will be used on the street. I'd be afraid of that aluminum just failing on me on a pothole or something.

A Pista is made out of steel, but it's not good steel, it's just your basic 4130.

Also, on any bike w/ nice steel tubing, the rear triangle is still going to be 4130. I don't know of any bikes that are completely 631 or 853 or w/e.

When looking at bikes, you should use the Seat Tube (c-c) as your measurement b/c ST (C-T) isn't as accurate. Most companies do C-C as well.

I think the Rush is a great frame, I just don't know if it will be much diff. than what you have now. If you need a new size, then go for it though. I do think that a carbon fiber fork would be your best bet, but if you really want a steel fork then get teh nicer tange model. I doubt you would ever have a problem w/ a CF fork, thoguh .

I figured you were talking about the Pista Concept. I definately don't want the normal pista with plain CrMo.

And I've done all of the measurements, and the 57cm should be around a 54-55 cm c-c seat tube.

Thanks for all the advice. It's much appreciated.