Is cutting down a HT extension on a Kirk blasphemy?

[scottcw]

In building up my Kirk Terraplane, I noticed that it has a rather long HT extension for my tastes. I looked up the specs and, sure enough, it is 3 cm. I understand that standard on a road bike is around .7 cm?

Now I am wondering if it is possible to cut the HT down so that I have more play to raise and, more importantly, lower my stem/bars.

Is this something that I should only let Dave do or could any good LBS in NYC do it?

Thanks.

[dirtdigger88]

You will need the paint redone- too- now the $$$$ go up

Jason

[csb]

my sawz-all is collecting dust

[Johny]

Do it. It is cheaper than plastic surgery.

[dirtdigger88]

my sawz-all is collecting dust

oh yeah- If you want to make it a D.I.Y project I have saws and cutting torches- I got the power tools- I am willing to play e-richie for a day

csb- you have to wear the white glasses though

oh no. . .let me guess- we are headed for gay vague- arent we :crap:

Jason

[Big Dan]

I have the feeling that the thick JB paint could be damaged......
Wouldn't do it...as soon as that blade hits the paint....... :eek:

[csb]

relax _ i have a random orbital sander for that quagmire

[Big Dan]

relax _ i have a random orbital sander for that quagmire


Sure that and some Krazy glue to put the paint chips back together...
Great advice........... :crap:

[Louis]

If you want to see what will happen when you cut it just make the first cut higher than your final location. You can play all sorts of games, such as wrapping the HT with a few layers of masking tape, or any other "anti-chipping" things you can think of.

Louis

[csb]

csb- you have to wear the white glasses though

oh no. . .let me guess- we are headed for gay vague- arent we :crap:

Jason[/QUOTE]

shhhh! we don't wanna wake up the guy curled-up in front of the packy

[11.4]

OK, seriously ...

Cutting it down requires that the top face of the top tube be perfectly parallel to the bottom one (otherwise your headset will bind and other problems will arise). The only way to do this is with the head tube clamped in a frame-maker's jig. Needless to say, your finish will be toast. The heat and vibration of cutting will lose some paint as well, as will the use of the refacing tool, and this is a spot where (because of the amount of perspiration that hits the area) you really want a solid paint job. Most builders would want to remove the paint before cutting anyway.

This being said, I've cut down some head tube extensions to get the bars lower. In bare Ti, it isn't all that complicated. In steel, the obligatory paint job makes it a bit more expensive. I'd suggest you send it back to Dave for modification, and at the same time think up anything you might possibly want to add to the frame (fender eyelets, pump peg, whatever -- anything that would occasion a repaint anyway). Dave is a superb builder and the right guy to do the job. He certainly won't put you to any unnecessary expense or hassle on the modification. Trust him.

[Jeremy]

Hi Scott,

Just an observation. What is the total HT length. With the relatively small variation in axle to crown dimensions and headset stack height, it is the total length of the head tube, not the extension that affects minimum bar height. A 3cm HT extension looks kind of funny on a bare frame, but built up it looks more normal. In any case, before you decide to cut it, you should compare the total HT length of this frame to what you need.

If you must shorten it you may be able to cut it with tape around the head tube to prevent chipping, but w/o a saw guide, the cut will not be at all close to "square". No matter what, the head tube would need to be faced after the cut. It is possible to face a painted head tube w/o chipping the paint, but you may be unlucky and have the paint chip anyway. Good luck

Jeremy

[Dr. Doofus]

if and only if is dave kirk god?

[Kevan]

and check to see if David's okay? Newspapers are beginning to collect on his driveway and he hasn't been seen outside playing in his front yard.

[BumbleBeeDave]

. . . You went through what I assume were lengthy consultations with Dave about fit, specs, riding style, and details of the frame. You have not even finished building it up yet, nor ridden it, if I am understanding your post correctly. Now you want to modify it before you’ve even ridden it?

What evidence do you have, aside from being able to POTENTIALLY play with stem and bar height, that this bike would not fit you perfectly exactly as is?

I have the greatest respect for Dave Kirk’s skills as both a builder and fitter. I am certain her has applied those skills 100% to trying to make sure the frame fits your body, your riding style, and your visual appearance desires.

I think you owe it to him--and to yourself--to finish building up your bike and go out and ride it some before considering doing this. You will probably find it fits perfectly as is and there is no need to play with the stem/bar height. And if you DO still decide to have it modified, then talk with Dave first and send it back to him. He will treat you right.

BBDave

[christian]

BBDave, Scott bought the frame used.

I would probably build it and ride it a season before deciding what to do, but if you decide to go ahead, I would talk to Dave first.

If you decide to have it done locally, I'd probably consider Vicious Cycles in New Paltz to do it. They could cut and face the tube and ensure that parallelism was still achieved. I wouldn't worry too much about paint chipping - after they cut it, they'll have to face the HT just like on a new bike. HTs are faced after paint all the time.

- Christian

[BarryG]

.

[scottcw]

. . . You went through what I assume were lengthy consultations with Dave about fit, specs, riding style, and details of the frame. You have not even finished building it up yet, nor ridden it, if I am understanding your post correctly. Now you want to modify it before you’ve even ridden it?

As Christian posted, I bought it used, so the specs were for another rider. I have no doubt the ST and TT measurements are fine, I just do not want to be stuck with the bars too high.

[scottcw]

I would probably build it and ride it a season before deciding what to do, but if you decide to go ahead, I would talk to Dave first.

If you decide to have it done locally, I'd probably consider Vicious Cycles in New Paltz to do it. They could cut and face the tube and ensure that parallelism was still achieved. I wouldn't worry too much about paint chipping - after they cut it, they'll have to face the HT just like on a new bike. HTs are faced after paint all the time.

- Christian

Thanks Christian. I called Vicious Cycles and they said they could do it with no problem. They estimate $50-60, but a month due to backlog. I am going to ride it as is for the rest of this year, then take it to their Manhattan shop to have it done in the offseason.

[Brian Smith]

Do you have a head tube reaming/face milling tool?

It is common for the top of the head tube to have its paint removed anyway, since folks face mill the head tube just before building frames into bikes. As long as you don't slip and remove paint elsewhere, and as long as your cut is straight enough to restore parallel faces with a mill, then I don't see any harm in cutting down a head tube extension.

$50-$60 is pretty cheap to make someone else liable for doing it right, but a month is not exactly overnight service.

Blasphemy it is not, risky it may be.

[djg]

pretty invasive way to address what might be a minor problem. There's a pretty good variety of stem and bar combos out there. Depending on what you have now, it might be pretty easy to drop the top of the bars a couple of cm and the bottoms more than that, just by switching stem, bars, or both. I'd be inclined to look at some of my options in that area before having somebody perform surgery on the head tube.