The bolts on my Renthal Duo stem are looking a little crappy, and as I like things to look nice I was going to change them for titanium ones, I’m not a weight weeny but thought they would probably look nicer for longer.

However, I’m not sure if they’ll be strong enough!! I ride all mountain/enduro, pretty much all uk trail centres, off piste trails but also hit up a lot of local spots, will I be ok using these bolts on my stem or is there a chance of them snapping?

Thanks all 🙂

They’ll be strong enough, as long as you ensure they are quality ones – therefore, just go with steel, and replace when ‘crappy’.

same strength as steel but two thirds the weight.

So, worth an upgrade then?!

A4 stainless?

Mine have been fine.

There used in the aerospace game, so if they are good enough for planes, helicopters and rockets am sure you will be fine 😉

Cheers guys!

I’ve replaced all of mine with stainless steel. I’ve also machined a taper on most of them to look like Ti. 😳

Does anyone know if they’re a specific length? 20mm seems to be standard on eBay, and I’m assuming I’d need M5?

If they are as strong as your cliche game, they will hold up to whatever you throw at them.

The ones that screw up from underneath on the Renthal stem probable need to be a specific length

check Pro Bolts for all nuts
,bolts,washers,cross drilled cap nuts in gold ,purple haze in ti.

since the instructions say stem bolts are tightened to 4, 5, 6 and 10 Nm only they should be strong enough. Only likely to snap if over tightened I would have thought

FWIW I tend to use cheap chinese crap 😉 Never had a problem with the strength of the bolts but the quality of the heads varies which does mean you’re more likely to round them out.

I suppose it would be wise to measure the bolts before I buy!

Ti bolts on my Thomson stem for 3 years for the same reason as you, get sick of rusty bolts. The bike get’s hammered and I have had no issues whatsoever with strength or slippage.

I suspect all ti bolts are made cheaply in China/Taiwan etc but some are fancy packaged as something better so they can charge a fortune. Mine are cheap Taiwan jobs with no issues.

They may well be as strong but they won’t be as stiff. In aerospace applications the joint calcs will account for the material.

But this is a bike part, not an aircraft, and I doubt you would notice it on something torqued up to 5 nm. Saying that I prefer to use steel bolts as I trust steel more than titanium.

I’m glad in not the only one to have issue with renthal bolt quality (my duo stem that was new in December has signs of the onset of corrosion around the base of the bolt heads.

I work in the aircraft industry and titanium bolts will be more than adequate for a bike. In aircraft high load points still use steel fasteners due to the higher shear strength (think engines, rotor heads, blades, gearbox mounts).

3T ARX Team and LTD stems come with Ti bolts as standard. As do Tunes Geiles Teil stems.

And ENVE

And probably some others too………

Giant’s Contact stem comes with Ti bolts…

Another area of high stress is brake calipers – my Hope SE brakes came with Ti bolts. I would never question Hope’s choice of fastener !

Loads of stems come with ti bolts. They’ll be fine!

Cool, thanks for all the feedback.

Just need to make sure I buy the right length!

They’re quite possibly M6, don’t assume M5

M6 are larger aren’t they, or is it the other way around? I know they’re quite small on the duo.

Yeah, the M number is the outside diameter of the thread, so it goes up as it gets thicker. Most stem bolts are M5 or M6. It’s possible to check it with a ruler but quite easy to get that wrong tbh, you learn to do it by eye over time, calipers work but most folks don’t have those! Course, you need to get the length right too. (adjustable spanners often have really dubious rulers on them but that would be accurate enough for this job, btw)

If in doubt, you could undo one of the bolts attaching the brakes to the frame (ideally, if you have an IS-mount rear brake, as that’ll avoid moving the brakes around). These are always M6 so you can compare. Or, obviously if you’ve got a spare one lying around use that!

Aaron, just email Renthal. They’ll get back pretty quick on what size bolts are needed.

P.s you ride xc, you ain’t kidding no one 😉

Ti will be more than fine

same strength as steel but two thirds the weight

same strength as steel but ONE third the weight…. well that is always what get quoted since the density is ~60% different. In practice a Ti bolt is around half the weight of the equivalent steel bolt.

Ever the weightweenie 😉

Torontocycles are worth a look for cheap, good quality (and even coloured) Ti bolts.

Haha, nice one banks!!! Ill be riding rampage next year!!

I did email Renthal a while back but can’t seem to locate their email address, do you have it?

Cheers DanW, I’ll check them out.

same strength as steel but ONE third the weight…. well that is always what get quoted since the density is ~60% different. In practice a Ti bolt is around half the weight of the equivalent steel bolt.[/quote]

Titanium is not 1/3 the weight of steel.

http://chemistry.about.com/od/elementfacts/a/titanium.htm:

Titanium is as strong as steel, but it is 45% lighter. The metal is 60% heavier than aluminum, but it is twice as strong.

http://mrtitanium.com/density.html –

Titanium weighs about 4½ times as much as water, iron and steel weigh about 8 times as much

no issues with ti stem bolts here.