mastershake916

Hello all. I've researched online but have not found the information that I need. I'm looking to find the dimensions (particular the outside diameter) of the part of the Park Tool clamp head that interfaces with the stand for the non-tapered non-grooved style.

I recently acquired a pre-1996 Park home repair stand, that I believe is the PCS-1 model. This utilizes a simple bolt rather than the more complicated knuckle mechanism that the professional style stand has. In turn the clamp head interface has a groove in it accommodate the end of the bolt.

From my measurements, my stand will accept a 50mm diameter clamp. If the non-grooved clamp head is also at or slightly below 50mm, then I'm sure I can make it work with some modification, which opens up the possibility of either the (in my opinion superior) micro-adjust style head, or a cheaper used clamp head.

Thanks for any help!

RGMN

I have that exact stand. The "lands" on the clamp head are 50mm, the groove is 46.3mm. And the shaft is 19.25mm

mastershake916

Thanks RMGN, I absolutely appreciate the response, it's great to know the dimensions of the the stock clamp. However, I'm looking to find the dimensions of the ungrooved version, to see if I might be able to use one of those (with some finagling).

fietsbob

A superior head comes from efficient velo tools https://www.efficientvelo.com/tools/...m-repair-clamp
Hand made in Portland Oregon .. with the crank you can close the jaws with 1 hand.. While holding the bike up with the other.

WizardOfBoz

My setup looks pretty much like the clamp below, if that's what your after. Larger diameter is 50mm, smaller is 19mm. Plus or minus. It's in an old Park PRS-5 stand, which I love. I think that the only difference that the groove gives you is centration. You probably can use one like mine (without groove) if you pay attention to how far in or out the clamp shifts.

WizardOfBoz

Good heavens! It's nearly $400! It OUGHT to be a lot better.

If you are working on one bike, I think that the Park approach is better. You adjust a turnbuckle nut once, and then it's a quick flick of the wrist every time you put a bike in the stand. This approach would also work for a lot of different bikes if they had the same diameter tube you are clamping. For example, I used that same clamp design setting up 100s (perhaps 1000s) of Schwinn Varsities, Continentals, Orange Krates, and even Paramounts in the 70s. And since Raleigh tubes were about the same size, it work for Super Sports and the like as well.

The Orange Velo approach might be better in a shop environment where you deal with a lot of different size tubes to clamp to. And it would have to be a shop (or a real tool addict, one who's company has had an IPO) to justify the $375 for the Velo clamp. You can get a used Park clamp on ebay for $40!

I'm sure I'd like the Velo Clamp. But I like the Park clamp, too, and I really like having the extra $350 in my pocket!

WizardOfBoz

I did some research and found that Park has a clamp that allows the cranking action of the Velo product. Can't say which is better. The Velo is nearly 200 bucks more. (100-3D is $187.50, Velo is $375), The Park does seem to have its center mass/clamp point aligned better with the mounting cylinder. It also has a cam action, so that you get close with turning the crank (and in fact you can clamp the bike using only cranking action) but also, when the adjustment is close, you can flip the cam handle and lock the bike in. Anyone have one of these?

fietsbob

Yea the red shop tool is A Small American manufacturing business, not a multinational..

mastershake916

Thanks for the replies everyone, exactly the info I needed!

RGMN

I have a version of that clamp in my PRS-25 stand. It's sturdy, fits almost everything, and holds a bike well once clamped but I find them a little fiddly to use. I never use the cam action, only the screw to clamp or unclamp. It definitely does not fit in the PCS-1 stand. If I recall correctly the diameter is wrong, and the post support is too short. Now if I could only remember where I left the stand.

RGMN

I seem to recall that those fit in the PCS-1 stand. The diameter and length are correct, and the PCS-1 clamping bolt will tighten on. The problem was without the groove the clamp would come out of the stand when rotating it. If you had a bike in the clamp at the time you could drop it.

WizardOfBoz

I wrote Park, and Calvin Jones was kind enough to respond. Apparently the small diameter part helps installation in some stands.

But you're right: there's nothing keeping someone from pulling the clamp, with bike attached, from the main part of the stand. And you can push the clamp mounting surface into the clamp, too. But this also would allow you to fasten the clamp to a bike and then install the clamp into the stand.

I was thinking that one could install a bushing, say, 15mm thick, with the 50mm od and a 19mm ID, in the mounting tube of the stand. You'd have to drill holes in the mounting tube to allow the bushing to be fixed. This would allow you to have three radial holes, drilled and tapped, into which screws would fix the bushing. Then a collar would fasten onto the 19mm diameter setup. Way too much engineering, I know.

One of the benefits of the PRS-5, though, is that you can disassemble it and pack it in a little carry-bag. To do this, you need to remove the clamp...

JohnDThompson 

Heh. We used those stands to hold frames for brazing at Trek. Nothing like having a red-hot bike frame drop in your lap while you're working on it! To prevent this, we brazed a little metal tab to prevent the clamp from sliding out of the stand while rotating.

Mad Honk 

A good search at Parks web site should get you the numbers for some of those clamp parts. I ordered repair parts for twelve stands in our co-op and was able to get them all from Parks. Try contacting parks directly as well they may be able to guide you through replacement parts search. Smiles, MH

mastershake916

Huh, really? The listed compatibly seems to be the same as the standard version on Park's website.

aggiegrads

The offset clamp is an essential part of the design of the EVT clamp. It allows much easier rotation of the bike because the center of mass of the BIKE is closer to the mounting cylinder.

If you’ve been to a shop with an EVT stand, it sits in a place of honor and all the mechanics fight over that workstation. That’s how it works at my favorite shop.

WizardOfBoz

The first paragraph makes sense. The second is valuable info for shop owners.

Only, I seem to recall clamping bikes closer to the crank on the Park-like design (I think it may have been an old VAR, below) to get a little closer COG. But I can see how the offset might help provided you are clamping the seat tube and not the down tube.

WizardOfBoz

Ah, I went to the velo website and it says "the first seat-post specific clamp". I have to clamp my bike by the seatpost (anywhere else would crush the CF tubes), so this would definitely be useful.

If I owned a shop, I'd probably have one. Since I don't, I'm going to have to live with the Park which has worked fine for me.

mastershake916

Just a quick update. I got a standard non-grooved clamp and it works great! Holds tight without any unwanted rotation. It will pull out if loosened, but this isn't any different than the professional style stand.

veganbikes

EVT makes some great stands though if I could I would do Park electric assist stands all day every day, it makes work so much easier and especially if you have heavy bikes or in the case of one of our mechanics who has some disabilities is allows them to work on bikes still without needing another mechanics help lifting a bike. The full EVT hydraulic lift was nice but the electric Park is better in that aspect but in clamping and rotating the bike I think EVT wins quite easily.