Tandem Tom

Thought you fellows might be able to help me out!
I would like to check the alignment on my fork of my touring bike. The best way for me to describe it is how do I make do I check if one fork blade is forwadf or back of the other? Would I use an dropout alignment tool? Next how do I determine that the blades are equal disanced from the centerline of the steerer tube?
I am try to see why my Tubus Tara is not centered on the wheel. The wheel s correctly dished.
Thanks for your help!

unterhausen

Forks have an interesting issue with alignment. A fork can be perfectly aligned from a steering geometry perspective, and catywumpus from a cosmetic perspective. This may be the case with your fork.

I suppose the first question to ask is, are the spaces on either side of the wheel to the fork blades equal?
What kind of fork is it? Unicrown, lugged crown?
Also, if you take the fork out and put it on the table, then measure the height of the dropouts from the table.

Tandem Tom

Mine is a Surly LHT fork. I will start the diagnosidi process!! Thanks!

Andrew R Stewart 

Tom- I will use the steerer as the base line and sight through it and the rim's valve hole to the rim's other side. The rim's centeredness both at the crown and also as spotted across the rim is the goal. The tire's contact patch is centered with the steering axis. I have various lengths of smaller diameter tubing using a couple of masking wraps "shims" to keep the tube centered and also adjust the fit far ant steerer. This works surprisingly well...

I'd add the link to my lengthy post on this method of centering a fork as well as other fork aligning issues, But I'm on my lap top which doesn't have the files or links. In a motel in Denver on the way to a Adventure Cycling Assoc. tour worried about the coming trio of hills, heat and height.

Tom- Email me after June 3. I'll be back home and starting to catch up. I'll be happy to share more. Andy

CliffordK

This is the tool you need:

https://villaveloframes.wordpress.co...ignment-gauge/

Park Tools FT-4

One end clamps the steer tube. Then you can run the bar along the entire length of the fork blades to see if they are even on both sides in both horizontal and vertical.

Then use a dropout alignment tool to set the dropouts.

One popped up on Craigslist a few days ago. I can get some more details if you need.

I would assume some of the better supplied shops dealing with vintage bikes would have one.

unterhausen

that tool is okay, but I wouldn't go out of my way for one. How much was it on CL? Best part is you can use it to hold the fork as you bend the heck out of it. Not going to do that with my Anvil fork fixture

CliffordK

Hard to say... I didn't get the fork bending tool, just the alignment tool.

But:
The whole pile for $200.

Not everything is in perfect condition, but I figure that I can pick out what I want, then decide if I want to sell or give away anything that I don't want.

fietsbob

Tip alignment is only the tip blades can be bent ou as well ..

Park has made a bike shop reference tool .. that the fork out of the bike is held in ,

the tool, is itself held in a bench vise..

maybe put a 1" tube through the steerer and see how far apart the tips are from that centerline,

Doing a lot of business in high end bikes?, there are precision surface table based , furniture for fork & measurement with precise dial instruments fro Starrett, etc




...

JohnDThompson 

Yes, the FT-4. Not sure if it's still in production, though:



More like a 7/8" or even smaller, but the concept is sound.

unterhausen

Since almost all steerers are butted, it might not be that great to reference off the inside of one. Seems like a table and a couple of books is a good start for a job like this.

yeah, that's worth having for that price. I always wanted a TS-2, but I settled for a TS2.2

Andrew R Stewart 

Tom got a good deal for a nice price. I'd have bought the pile for the FT-4 and sold off the rest. Not because I think it's the best tool for aligning forks but I'd like to add to my collection of frame tools in general. Andy

unterhausen

yeah, a month ago, I thought about buying an ft4 and never saw one for a reasonable price, so I gave up.

I like Park's bender lever a lot, but I forget what their part number is on that.

fietsbob

Maybe 1" threaded . that was true,
But 1.125" threadless steerers are not butted, they rely on the added stiffness of being a larger diameter..

Andrew R Stewart 

True Temper made a couple of different 1.125" steerers with a butted crown end. The touring bike that sits at my elbow right now uses the heavier version.

As to using the insides of a steerer as a reference surface and having it butted are not incompatible. The sighting tubes I make for my "home grown" alignment methods use masking tape wrapped many times around the sighting tube's OD. It's easy to just stop winding the tape at a point where it will slide into the Steerer. Both the full ID (where the thinner tube walls are) portion and a slightly smaller ID portion where the butt transition is. If the sighting tube is wrapped well and evenly it will sit at the steerer's axis. By rotating the sighting tube within the steerer one can see any lack of centeredness. By having the tape build up nestle into the steerer's butt it snugs the sighting tube in place. Andy

Live Wire 

Every 1 1/8" steerer Ive seen has been butted...and Ive built more than a few forks.

fietsbob

how thick is the butt ? difference in measured wall thicknesses ,, is required for your answer to have meaning.

Live Wire 

They are butted, as in thicker at one end than the other, measurements depend on model/maker. I'm guessing you don't build a lot?

duanedr 

Agreed, every one I have ever seen or used, threaded or unthreaded, 1 or 1-1/8th inch, is butted.

fietsbob

I see you don't measure

duanedr 

Oh I measure! I'm measuring my words right now!!

fietsbob

ln mm ?,

unterhausen

I'm sure there have been straight gauge steerers, it's just that I am pretty sure I have never held a fork built with one in my hands.

I guess my work as a metrologist/precision engineer makes me reject the inner diameter of the steerer as a reference surface, but it does seem handy for certain tasks. Particularly since there are so few good reference surfaces on a fork.

fietsbob

lots of suspension forks seem to use a straight tube steerer, and work fine.

Andrew R Stewart 

Bike Pulls to the Left

I've returned to my desk top box and now can link to the previous post I made about simple fork alignment checks. The above link takes you to the thread and my lengthy post is #16 .

Eric- WRT the inside or the outside of a steeerer being used as a reference. Since butted tubes are formed on a mandrel (which is removed later) one could argue that it's the steerer's insides that are the first dimensional reference and that the OD is the secondary surface. Although I, and most, use the OD as their reference surface as it's easy to grab, secure and read from. As well as is what the frame sees. Andy

mikeread

I have Tubus front and rear racks and they are both all over the place. I wasn't at all impressed when I bought them, the rear rack fittings were woeful too and went straight in the bin.

They have been reliable and served me well for 15 years or so but I do still cringe every time I notice how wonky they are.

I should put the heavier pannier on the side that sticks inwards to balance things up but never do of course.