Technical FAQ
The paint and chrome work on Colnago's Masterlight...

Technical FAQ: Repairing a bent steel frame; mixing SRAM and Campagnolo

A reader survives a crash with an automobile, but his steel bike does not. How should he go about repairing the bent frame? Plus, mixing SRAM Rival and Campagnolo Record components.

Have a question for Lennard? Please email us to be included in Technical FAQ.

Dear Lennard,
I was hit on my steel frame bike squarely from behind. I survived, but the bike not as much. It has bent seat stays, chain stays, and fork blades. The main triangle appears to be undamaged. This frame was a custom build by Roland Della Santa using Columbus SLX tubing. Della Santa passed last May while my replacement frame was in progress, and I will not receive it. I would now like to have the damaged frame repaired at the expense of the driver’s insurance company. There is a frame builder who is familiar with Della Santa frames, and he can make the repairs. What steps should I follow to make sure the repaired frame is safe and sound? If I have the lugs on the main triangle x-ray inspected for cracks, and the main triangle analyzed for deflection, is it still possible to make the repairs and bring the frame back to its original condition?
— Dave

Dear Dave,
Glad you survived; that must have been a scary moment. It’s good you have a frame builder who can do that work on your beloved bike.

If you have a way to x-ray inspect the interior of the lugs in that front triangle, I’d love to see the results. My guess is that if there are no ripples in the main tubes near the lugs, and if the front triangle lines up properly on an alignment table, then there also will be no damage within the lugs themselves.

If there is any chrome on that fork crown, I would get a completely new fork. If not, and inspection of the crown and steerer shows no deflection or damage, then replacing the fork legs alone is probably okay.
― Lennard

Dear Lennard,
I have a six-year-old Shimano Dura Ace 11-speed rear shifter that intermittently does not make its normal inside stop position when depressed in making a down shift (to a smaller gear). It is only intermittent and does shift normally after returning to its stationary position, but you have to initiate the shift again. It is really quite disconcerting when it occurs, because it goes way past where it normally stops, and then of course the shift does not occur on the return, which is even more disconcerting. Any ideas? My local shop, which is usually quite good, thought I should have the cable replaced, which I did, but it did not solve the problem.

I sort of thought it was an indexing problem of some sort and that still seems to be the case.
— Story

Dear Story,
The pawl is not engaging the index gear to stop the return. It is unrealistic to get inside a Shimano shifter and replace parts; the parts are not available, and the levers are assembled by robots and not set up to be done by human hands.

What I recommend you do is blast spray lube up into that lever from the underside. It may free up the spring-loaded pawl that stops the rotation of the internal gear. I’ve seen this rehabilitate a number of non-functional Shimano levers in the past. Mentally prepare for the possibility of the lever not resuming normal function.
― Lennard

Dear Lennard,
When buying a new bike with disc brakes, I have noticed the levers stretch the reach. Should a buyer size down on the top tube length to get the proper position?
— Charles

Dear Charles,
Well, you could do that. Some of this is taken into account by the fact that most road modern road bars have shorter reach than bars did in past decades. Also, hydraulic levers are taller at the end; in some cases, a vertical master cylinder sticking up prevents the hands from being able to slide as far out on the lever as they could on cable-actuating levers.

It’s hard for me to imagine that you wouldn’t just go down in stem length by a centimeter if you think switching to a hydraulic lever makes the reach on your bike longer.
― Lennard

Dear Lennard,
I’ve read your article on mixing Campy Centaur 10 and SRAM RED. I’m interested in trying this with Record 10 shifters and SRAM Rival drivetrain, both from 2009. My local shop has said they’ve tried and couldn’t get it to work. Do you have any advice I can impart to the shop?
— Jonathan

Dear Jonathan,
Well, as I recall, it was pretty simple. It was not a Campy-equipped bike with a SRAM rear derailleur; it was a SRAM-equipped bike with Campy levers—all 10-speed. It worked quite passably; I used that setup for quite a while. I don’t know why the shop couldn’t get it to work, unless they were using a Campy 10-speed cassette, or perhaps a 9- or 11-speed cassette (of any brand).
― Lennard

More feedback on damage caused by stationary trainers and winter footwear

Dear Lennard,
I appreciated your recent suggestions on keeping your feet warm in cold weather. But as someone with feet that get very cold easily (I may suffer from a mild form of Raynaud’s Syndrome), I find the choices fall a bit short for me, and likely other riders. Might I recommend two others? Run flats with any boots you choose. Buy those boots a size larger than normal to fit an extra pair of wool socks. Or purchase 45Nrth boots. These are the boots of choice for those who fatbike in below zero Fahrenheit temps in Wisconsin, Minnesota and the UP of Michigan.

I receive no compensation or other consideration for recommending these boots.
— Kelly

Dear Lennard,
I wonder if the problem of front-end shimmy that Steve is encountering with his Cervelo R3 would be solved by going back up from a 90mm to a 100mm stem. I had a similar issue, and it seemed when I went with the slightly longer stem, my problems went away.
— Ben

Dear Lennard,
We just got two more bikes in for repair from trainer damage this week!

I spent 80 hours in the classroom receiving my ASNT Level 2 Ultrasound Certifications. We’re furthering our analysis of damage characterizations and usage, meaning how quickly certain Non-Visible damages propagate through a composite during “normal” riding situations.
— Shawn Small
Owner || Engineer
Ruckus Composites


Lennard Zinn, our longtime technical writer, joined VeloNews in 1987. He is also a custom frame builder (www.zinncycles.com) and purveyor of non-custom huge bikes (bikeclydesdale.com), a former U.S. national team rider, co-author of “The Haywire Heart,” and author of many bicycle books including “Zinn and the Art of Road Bike Maintenance,” “DVD, as well as “Zinn and the Art of Triathlon Bikes” and “Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.”
He holds a bachelor’s in physics from Colorado College.

Follow @lennardzinn