v8powerage

What's with bicycle part manufacturers penchant for threading steel bolts into aluminum. Most notorious are seat clamps, how hard is it to make this tiny rectangular out of steel instead of aluminum, in fact it would be cheaper, I replaced mine with regular nut because it kept creaking and just gave up one day.

Another thing is stems, I just broke Cinelli Frog stem, they expected M6 bolt (not even M7 like in most old stems) to hold it all together, (the two bolts on top only hold the plate in place) of course it's threaded into aluminum, now I need to insert steel helicoil, something that should've been done from factory.

Chuck M 

The threading together of dissimilar metals is always going to be necessary from time to time and can't always be avoided. Proper torque methods are important for this reason.

cxwrench

All righty then.

Andrew R Stewart 

If one thinks that long term durability is a primary goal of the current bike industry I would say you're missing why they are in business.

If one thinks their past experiences will dictate how current bike parts are dealt with I would say that's only partly the case. The advent of tiny sized bolts and structural composites makes how one deals with fasteners much more sensitive to torque levels.

Having said all that I do share the OP's frustration with some choices that we have to deal with. Andy

smd4

And grease on the threads.

easyupbug 

I have a custom with a frog and the two top bolts tension the bar with the lower bolt all being brought up to spec as I expected and is years in service.

JoeTBM 

I would most likely replace that bolts as well, the threads look a little buggered up, may want to try greasing the new bolt as well.

smd4

Ya mean like pedals?

Litespud

bear in mind though that pedal use coarse threads, which are harder to strip (though not impossible, obv) than the fine threads used in stem fasteners.
the most egregious example I know is automotive - each rear wheel on the Triumph TR6 is held on by 6 5/16” UNF studs threaded into soft aluminum. The torque setting/range for these is alarmingly low/narrow. A standard upgrade is to tap the holes out to 7/16” UNC and insert steel Keenserts with a 5/16” UNF internal threading. At least the fine stud threads are engaging steel

dedhed

With so many aluminium block & heads today automotive is the worst. At least with a wheel you can get at it.

v8powerage

Up to spec meaning? I can't find any manual. On mine the lower bolt is longer than the top ones , I tried to torque all three same force but that was impossible, top ones went all the way in then I was left with the bottom one bearing all the force so of course it stripped being only M6 threaded in aluminum.

Crankycrank

To me this is really a non-issue. Aside from the occasional poorly designed part, steel bolts in aluminum work fine, are plenty strong enough and usually fail due to user error from over torquing and cross threading. Most people want lightweight bikes and making everything bombproof gets heavy real fast. Mfrs. could install steel inserts in some aluminum threaded parts but it's not cheap and usually not necessary. Every owner is expected to obtain some mechanical knowledge before working on their own bikes and can get help through hundreds of outlets like here or YouTube, etc., etc. If someone doesn't want to learn they can let the pro mechanics handle it. OP was complaining that his stem handlebar clamp has 6mm bolts which are pretty standard for the hundreds of thousands (millions?) of handlebar clamps in use and not a safety issue that I'm aware of.

Crankycrank

Did you gradually increase the torque on all three bolts making at least three passes of equal torque before getting to the final pass and make sure the faceplate had equal gaps at the top and bottom?

cyccommute 

That’s not a torque issue. It’s an assembly issue. For a faceplate style stem, you should be able to assemble the faceplate so that the gap between the plate and the stem are equal at all bolts. Then you torque the bolts. If one of the bolts is long than the others, you should replace that bolt with one of the same length. Either cut it down or get a new one.

My other question is are you sure you are using the proper diameter handlebar? Are you trying to use a 25.4mm bar in a 26.0mm stem?

Finally, there is nothing on a bike other than crank bolts that needs super high torque. If something seems to need extreme torque, check to make sure that it is installed properly or if there is a fit issue. I’ve run across a whole lot of parts that some gorilla tightened. It’s unnecessary.

70sSanO

I agree that seatpost clamps/collars should have steel bolt and a threaded steel insert. There are just too many variables, the primary one probably being rider weight, that requires more torque to keep some seatposts from slipping. I know Salsa made one that incorporated a steel barrel nut.

As for eliminating threaded steel fasteners/adjusters on a bike, that would be nearly impossible. Almost every component has some steel threads into aluminum; limit screws, barrel adjusters, freehub bodies, pedals…

While some applications might benefit, I doubt anyone sees value in a complete overhaul of components.

John

easyupbug 

"Spec" meaning exactly what Crankycrank said above, alternating torquing, gradually, and obviously greased, but I just pulled my cap off and I have one M6 that is 3mm longer than the other two, the shorter rearward and the front the longer. They did not move with my 3 NM Torque key but it did not take much more to pull. I know repeated torquing of aluminum even with lube can cause thread failures but that should not be the case with a stem.

sweeks

Isn't this an integral part of "proper torque methods"?

HillRider

Not always. Easton made a series of 4-bolt faceplate stems called "Top-Lock". For these the two top bolts were installed and tightened until the faceplate bottomed against the stem. There is no top gap at all. Then the bottom bolts were installed and tightened evenly to spec leave a uniform gap left to right.

3alarmer 

.
...how hard is it to buy and install a couple of helicoils in a stem?

79pmooney

So I'm supposed to grease this thread? My screen? The keyboard? The mousepad? (Sorry, couldn't resist.)

I use lots of grease on all bike threads. I also like fasteners, especially those related to bike fit to be large enough and robust enough to be loosened and tightened many times. Yes, steel nuts and thread inserts where appropriate. Sadly these run against the concept of minimum weight. Always.

zandoval 

v8powerage

So Your faceplate has even gaps top and bottom? As for the bolts, the bottom bolt is original and is longer.
I was trying to do that, alternating torque and make it pull evenly but then top was very loose and handlebar wasn't secured at all. Handlebar is 26mm I measured it with caliper.

easyupbug 

Wow, I got nothing. It had been so long I tried finding Frog instructions and found this:https://www.sjscycles.com/Instruction...structions.pdf
Written by lawyers, it actually says for "Occasional Amateur use - "replace the screws of each component /w original Cinelli spare parts every 2 years"!

Crankycrank

There is also a slight possibility that this is a 26.4 clamp. Cinelli started making the Frog about the same time they were switching from 26.4 to 26.0. Not sure if the Frog was ever even made in a 26.4 though so take the handle bar out, bolt the faceplate down and measure the I.D. A longshot but worth a try.

v8powerage

Well I don't know how to assemble this faceplate the bottom bolt is longer and it acts like the single bolt clamp that's how I see it and the thread is aluminum (stupid). I'm gonna get helicoil but it has to be special thin walled kind because there's not much space there I can only drill to 7mm, regular ones need 10mm hole. Meanwhile I put back modolo race with bolt and nut which is tightened as hard as I physically could if it strips I get new nut.