been looking on CRC and looking for a decent hardtail and saw the curtis range and thought that would be cool but then saw the price ! Is the frame material uber strong steel, light weight etc …I have never seen one on my travels !

Depends on the version. Try looking on the Curtis site.

I have a pro street and it would survive a nuclear war.

The workmanship and brazing especially is a thing of beauty but the standard frames are perhaps old skool however you ca go bespoke if you want something special.

that looks nice is it steel ?

I had a Curtis Expert BMX which got stolen and a Curtis Freestyler which i sold for peanuts and the welds were perfect , i so wish i still had them .

You can get this information from their website but….

The expensive ones you see on CRC are all handmade, either from T45 or 853 steel. Curtis only builds in steel.

They do make cheaper frames from standard 4130 steel.

They are expensive because they are all made by one guy – Gary Woodhouse – at a rate of one per day. If you want, he will build whatever you desire, much like Nicolai and 18Bikes will (although he does work from a basic template and you get to custom spec the angles and lengths etc. I think 18Bikes start totally from scratch. In this way, Curtis are like a tailored suit whereas 18Bikes are like a bespoke suit).

They are fabulously well made and finished, with very high attention to detail.

Will they ride better than a Cotic Soul or something similar? I doubt it, unless the ride characteristic is inherently about having custom geometry.

Would I chose a Curtis over a Cotic if someone were offering it to me free? Yes, more than likely, they are deeply covetable creations.

One thing to bear in mind, and I am not 100% sure this is true but I have read it elsewhere. Curtis ‘braze’ their frames rather than TIG weld them. The brazing material melts at a lower temperature than TIG welding works at so consequently the metal is heated to a lower temperature. I’ve read that in order to get the maximum air hardening qualities that 853 steel provides, it needs to be TIG welded, not brazed as the latter process doesn’t heat the metal to a high enough temperature.

If that’s the case, then it may be as good to get a T45 model rather than an 853 one? You might be paying extra for a quality that isn’t being realised?

But like I say, I’m not 100% sure on this.

After welding the air hardening properties allow the steel to mostly recover from the the loss of mechanical properties due to the welding.

I think brazing is about 450c which isn’t hot enough to anneal an air hardening steel anyway so, it won’t lose any of its awesome properties during brazing. In which case the 853 in a curtis frame will be at peak performance, probably better than if it had been tig welded.

nice ride mundiemeister

I think brazing is about 450c which isn’t hot enough to anneal an air hardening steel anyway so, it won’t lose any of its awesome properties during brazing.

That’s interesting. But I thought that a lot of the strength of 853 actually comes from the air hardening, rather than an inherent strenght before it’s heated.

I’ve obviously not understood something so would genuinely appreciate the explanation.

AFAIK 853 hardens at the welds, I don’t think that would happen with brazing so you are not getting that benefit, but you are getting the benefit of lighter weight of 853, albeit brazing is heavier than welding.

I think you are most definitely paying for quality that isn’t being realised if you buy a Curtis or similar unless you are getting custom.

AFAIK 853 hardens at the welds, I don’t think that would happen with brazing so you are not getting that benefit, but you are getting the benefit of lighter weight of 853, albeit brazing is heavier than welding.

Yes but I thought that 853 was made lighter precisely because it has this air hardening property, i.e. because it could be made stronger through the fabrication process, it therefore needed less material, e.g. shorter butts in the tubes, thinner overall wall thickness etc.

Is it then the case that if you fabricate in such a way as to not realise this propery, you’re actually getting a weaker frame?

It’s strength does come from its air hardening, its air hardened before it leaves the tube factory. With high strength steels their properties get ruined (locally, at and near the weld) by welding. The challenge is to get those properties back. Air hardening steels recover those properties on their own, after welding, in air (mostly).
So before welding they are hard, during welding they soften, after welding they harden up in air.

If they weren’t at full strength before welding, then only the weld and nearby would be at full strength after welding. You wouldn’t want that now would you…

Toys that’s a great explanation thanks for taking the time. Genuinely very interesting.

What toys19 says – spot on!

I’m planning to buy a white powdercoated Curtis T45 “freeride” custom with red anodised Hope kit and Middleburn for my 50th. Some years to wait, but something to really look forward too.

Always happy to help!
I just wanted to reiterate, a brazed high strength steel frame will be fine as the brazing temp is not enough to make any metallurgical differences to the steel, so it will remain very strong..

Brazing creates a smaller HAF than TIG, consequently better for joining exotic alloy heat treated steels.

My jump – playbike sort of thing 🙂