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-   -   Does this fork look bent? (https://www.bikeforums.net/showthread.php?t=1259410)

52telecaster 09-29-22 07:51 AM

Does this fork look bent?
 
https://cimg3.ibsrv.net/gimg/bikefor...e736ba520d.png
The seller says front fork spacing is pinched to 90mm. It's a 1979 trek 710 for a pretty reasonable price and I know I can spread and center the fork tubes but I am worried the stearer may be bent. Best pic I have..... Any advice?

Steelman54 09-29-22 07:58 AM

At times hard to tell but from this photo the fork looks bent to me. Seems to be pushed back a bit.

52telecaster 09-29-22 08:03 AM


Originally Posted by Steelman54 (Post 22663067)
At times hard to tell but from this photo the fork looks bent to me. Seems to be pushed back a bit.

That's my thought but it helps to have confirmation.

Mr. 66 09-29-22 08:08 AM

Could be pushed back, but if it is it can't be by much. I would look at how the fork crown and upper hs looks in relation to the cups in rotation. Variation could indicate a bend. I would certainly go take a look at it, if it rotates clean and even go for it. Even if it has had some front impact that would be addressable.
https://cimg2.ibsrv.net/gimg/bikefor...b1f7a9cb3d.jpg
I lightened the picture, and I can see some daylight between the forks. Could be some optical illusion as well.

seypat 09-29-22 08:23 AM

Looks bent to me. If you could swing the fork around where the blades were aligned to the pic taker's view, it would look even more bent.

Charles Wahl 09-29-22 08:51 AM

https://cimg2.ibsrv.net/gimg/bikefor...95d3e87ec3.jpg
Based on the photo, the seat tube looks a bit more relaxed than the head tube, but the fork blade centerline seems to be steeper even than the head tube. I would pass on it.
OTOH, if you wanted to gamble that at least the frame isn't bent, I have a decent Trek 7xx(?) fork supposedly with Ishiwata tubing, in that color, has reinf. tangs extending from the crown down insides of fork legs, so-so cosmetic condition, that I would offer for not a lot of dosh. It is from a larger frame: steerer 24.5 cm long with 6 mm of thread, so it might have to be cut down and (harder) rethreaded to fit. PM me for more detail.

Doug Fattic 09-29-22 09:00 AM

I've aligned hundreds and hundreds of steel frames in my career. It is rare that a steerer is bent. They are awfully thick. This one looks like a normal head on bent back. What is much more likely than a bent steerer is that the down tube and top tube are buckled a bit right behind the lugs. Feel carefully right behind those lugs on the bottom of both to see if there is any damage. You don't want even a slight amount of a crease there. Treks of that era were never that well aligned in the 1st place so I wouldn't be surprised the main frame is out some too. It isn't a problem to realign what looks to be a fork that is bent back some. Of course I'm a framebuilder that looks at a project like this as being no big deal because I have all the right equipment and knowledge to make it right.

cudak888 09-29-22 09:04 AM

Not enough that it can't be cold set.

However, the seller's 90mm comment makes me thing it's bent side-to-side; e.g., if a Sturmey-Archer hub had been jammed into it at some time. Is the picture provided a "before" by chance?

-Kurt

Classtime 09-29-22 09:11 AM

My son crashed his 560 pretty good to destroy his front wheel, bend the fork blades, and bend beyond repair the top and down tubes. The steerer was straight. I cut the steerer off to make a headset remover and was surprised to find it so crazy thick. (710s are very cool and with that perfectly fitting rack....)

BlazingPedals 09-29-22 09:19 AM

You can always verify the bend and where it is by removing the fork from the frame and sighting down the steerer tube.

Schreck83 09-29-22 09:48 AM

IIRC, the Trek catalog showed the frame dimensions for all frame sizes in 1979 for the 710. Check the wheelbase against the brochure. If the price is right, could be worth it.

SJX426 09-29-22 10:12 AM

Example of a bent steerer.
https://live.staticflickr.com/5675/2...c4356164_b.jpgP1030228 on Flickr

Indication of magnitude of impact - 21 MPH into a car fender
https://live.staticflickr.com/5682/2...6a4e2085_b.jpgP1030232 on Flickr
https://live.staticflickr.com/5804/2...79d938ab_b.jpgP1030233 on Flickr
https://live.staticflickr.com/65535/...3f1e58b500.jpgP9051190 on Flickr

Lattz 09-29-22 12:11 PM

[QUOTE=SJX426;22663236]Example of a bent steerer.

Indication of magnitude of impact - 21 MPH into a car fender

https://live.staticflickr.com/5804/2...79d938ab_b.jpg
Now i have a rough guess what happened to the Gitane tandem i street picked for a begging friend.

cudak888 09-29-22 12:23 PM


Originally Posted by SJX426 (Post 22663236)

That's a bent steerer and a bent crown.

-Kurt

Kabuki12 09-29-22 02:07 PM

SJX426, I hope the rider was ok. That looks serious to me. At 21 mph a person can get waded up pretty badly. The OP bike is worth looking at with caution as mentioned . The DT and TT lugs at the head tube should be inspected closely as well as the fork. Also head tube for cracking , my friend had a Circuit and after a front end crash that apparently only taco'd the front wheel and a year later the head tube broke ....apparently we didn't check it good enough, DOH!

madpogue 09-29-22 02:30 PM

What's the ask? Option: low-ball it based on the risk of bent top/down tubes, offer what you think the bar-ends and the Blackburn are worth, the rest is (if wavy...) gravy.

52telecaster 09-29-22 06:12 PM


Originally Posted by madpogue (Post 22663583)
What's the ask? Option: low-ball it based on the risk of bent top/down tubes, offer what you think the bar-ends and the Blackburn are worth, the rest is (if wavy...) gravy.

Honestly the barcons caught my eye first. That it was a 710 next. Just not sure I want another project.

cudak888 09-29-22 08:13 PM


Originally Posted by Charles Wahl (Post 22663134)
Based on the photo, the seat tube looks a bit more relaxed than the head tube, but the fork blade centerline seems to be steeper even than the head tube. I would pass on it.

The photo has inherent distortion in it from the lens and looks as it may have been cropped too. Wouldn't use it as a guide.

Front end could also be pointing just slightly to the right as well.

-Kurt

AdventureManCO 09-29-22 08:28 PM

It looks similar in the photo to my Gitane TdF in real life, in that I *think* there is a bend, but it is light enough that it makes me wonder. I'd go take a look at it and see it in person, check the fork, check the downtube, and proceed from there! Good luck!

uncle uncle 09-29-22 09:52 PM

I just purchased a bicycle with a bent fork. In my case, the steering tube portion of the fork didn't have a discernable gap with the frame head tube (indicating a fork that's bent in the lower part of it's steer tube portion). Plus, there was no binding or looseness when rotating the handlebar. But, the positioning of the brake shoes on the front fork in relationship to wheel rim, in comparison to the positioning of the brake shoes-to-rear wheel rim is different. The front brake shoes were positioned lower within their slots, to compensate for a bent back fork.

cyclophilia 09-29-22 10:02 PM

There will be other opportunities
 
Unless you are entertaining this as a “parts bike” I recommend that you wait for something nicer.

This model was mass produced: there will be others.

Velo Mule 09-29-22 10:20 PM

Does this fork look bent? No. It is fine. That is based on my thoughts listed below:

1. For some reason forks have a tendency to look bent in pictures.
2. The tendency for forks to look bent are higher on Online Forums like BikeForums because we all want to error on the side of caution and we want to save our fellow forum member from wasting their time and money.
3. Despite @Charles Wahl 's excellent picture with the lines, I think that the deviation that we are seeing is from the taper on the fork.
4. While it is curious that the fork over locknut dimension is 4mm too narrow, that is not an indication of a bent fork. They are two separate issues. If the bike crashed the fork would still be 100mm apart because the fork legs are held in position by the hub unless the wheel came off in the crash.
5. I am optimistic about this
6. And I tend to be contrarian.

These are only thoughts based on one picture. It is worth the look if the price is justified.

I know you will check it out and test ride it before you buy it.

Good luck @52telecaster . We will wait for the verdict and pictures if you do purchase it.

Doug Fattic 09-29-22 11:53 PM

I think this sport touring model of Trek was brazed with lower temperature silver instead of brass like they did later as a cost cutting measure. These earlier Treks used Nikko lugs. I really like Nikko lugs because they are bulge formed and many of my frame building class use them. They are the only company that make lugs that way. Also the frame is made for 47/57 mm brake reach allowing for bigger tires. It became more popular to spec with shorter reach brakes when narrow tires became popular. In fact someone gave me this same model of Trek for our Ukraine Bicycle Project. We used to do week long rides somewhere in the Ukrainian boonies for a number of years. I fixed up this model as my personal ride and have loved ridding it for thousands kms. What I recall is that the frame when I got it was not well aligned to begin with. Trek never had high alignment standards for their steel frames. Of course I realigned it, redid the braze-ons to my liking and repainted it a chameleon color. I replaced the parts with a used Campy Triple set. I even took over a Ideal 92 saddle for it. It was my personal ride when going longer distances. Students at the college where our frame/bike shop was located loved going on rides with me in the Bucha area after supper. It was a loaner to people that worked on campus when I wasn't there.

This bike was stored in a shed next to our little frame/bike shop. In March of this year the Russians broke in to the shed but - to prove they didn't know what they are doing - they left this bike and 2 other Trek sport touring frames. In fact the door to the shed was wide open for 4 to 5 weeks before people were able to return to the college and finally shut and lock the door. I'm not sure what was in there that they did take. Some bicycle stands I think. Yuriy my fellow helper took this picture when he made a quick trip back after he escaped to the west.

If I was looking for a nice sport touring frame, I would buy this bike - in whatever condition it is in - in an instant. Of course it is so easy for me to the realignment because I have all the professional equipment to do so. If you are going to buy it for parts only, send me the frame! I'll pay shipping. It will go to Ukraine with our next shipment of stuff. It is a perfect bike for riding longer distances on poor roads. There is going to be a much bigger demand for bicycles than ever over there.

https://cimg9.ibsrv.net/gimg/bikefor...b96c72147d.jpg
My Trek sport touring bicycle and a couple of others the Russians didn't bother to steal after they broke into this storage shed. You can see from this picture that they didn't bother tidy up after they broke in either - the animals.

52telecaster 09-30-22 06:26 AM


Originally Posted by Doug Fattic (Post 22664035)
I think this sport touring model of Trek was brazed with lower temperature silver instead of brass like they did later as a cost cutting measure. These earlier Treks used Nikko lugs. I really like Nikko lugs because they are bulge formed and many of my frame building class use them. They are the only company that make lugs that way. Also the frame is made for 47/57 mm brake reach allowing for bigger tires. It became more popular to spec with shorter reach brakes when narrow tires became popular. In fact someone gave me this same model of Trek for our Ukraine Bicycle Project. We used to do week long rides somewhere in the Ukrainian boonies for a number of years. I fixed up this model as my personal ride and have loved ridding it for thousands kms. What I recall is that the frame when I got it was not well aligned to begin with. Trek never had high alignment standards for their steel frames. Of course I realigned it, redid the braze-ons to my liking and repainted it a chameleon color. I replaced the parts with a used Campy Triple set. I even took over a Ideal 92 saddle for it. It was my personal ride when going longer distances. Students at the college where our frame/bike shop was located loved going on rides with me in the Bucha area after supper. It was a loaner to people that worked on campus when I wasn't there.

This bike was stored in a shed next to our little frame/bike shop. In March of this year the Russians broke in to the shed but - to prove they didn't know what they are doing - they left this bike and 2 other Trek sport touring frames. In fact the door to the shed was wide open for 4 to 5 weeks before people were able to return to the college and finally shut and lock the door. I'm not sure what was in there that they did take. Some bicycle stands I think. Yuriy my fellow helper took this picture when he made a quick trip back after he escaped to the west.

If I was looking for a nice sport touring frame, I would buy this bike - in whatever condition it is in - in an instant. Of course it is so easy for me to the realignment because I have all the professional equipment to do so. If you are going to buy it for parts only, send me the frame! I'll pay shipping. It will go to Ukraine with our next shipment of stuff. It is a perfect bike for riding longer distances on poor roads. There is going to be a much bigger demand for bicycles than ever over there.

https://cimg9.ibsrv.net/gimg/bikefor...b96c72147d.jpg
My Trek sport touring bicycle and a couple of others the Russians didn't bother to steal after they broke into this storage shed. You can see from this picture that they didn't bother tidy up after they broke in either - the animals.

I'm not sure I will buy the bike but I am sure that your contribution to this thread was wonderful.

Reynolds 531 09-30-22 12:04 PM

"Does this fork look bent?" is the BikeForums C&V equivalent of "Does this look infected?"


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