Hi,
I’m just about to get my twin-shock rear springs re-chromed. I was asked if I wanted bright or dull chrome! Apparently, dull chrome has an undercoat of dull nickel plating and provides a more matt, less reflective finish than bright.
Before I part with my cash, does anyone know the answer? What would it have left the factory with? I presume bright, but thought I would ask before I made a mistake…
Thanks.

I know of bad experiences chroming stressed high strength steels like springs...  look up "hydrogen embrittlement" and ask your plater about it.

Nickel is the "shiny" part of the chrome...  pretty sure many springs were only nickel plated to avoid embrittlement problems but I don't know what Yamaha did.  (The way the stock springs rust it wouldn't surprise me if they are only nickel plated.)  Chrome is actually clear and provides a protective coat over the nickel. They can "bake" the hydrogen out after chroming but the high temps involved could potentially take the temper out of the spring.  It can be done but you need someone who is familiar with the processes.

Also, my guess is "bright" nickel is going to be more expensive because the difference is likely just polishing which may not be easy to do on a spring. (And why you'll often see the inside of springs are dull)

My generic suggestion to this topic is I ask my local chrome shop what is the price to rechrome a specific item and then I look on eBay for a NOS and if it is close to the same price I buy it. For rear shocks there are repops by Assault and Redwing that fit the '68-'73 Enduros that look pretty close to original. I have them on 2 of my regular riders.

Also as Mark said be careful about rechroming old parts and springs.

I am not much use when it comes to chrome work however i did talk to DEET last week about this subject, he mentioned a few different processes. For the rear shocks you have to be careful that you dont have it so the chrome cracks when the springs compress and retract. I cant remember what process he recommended for those. Same goes for the front forks i think you want what he called "hard chrome" that way the tubes are the same diameter all the way up and down. Hopefully he will be along to input his vast knowledge but i thought i would at least throw this out there.

Thanks for your messages. I’m sorry if this question has been asked before (I’m sure I’ve seen it), but does anyone know of a UK supplier of rear shock springs that fit the standard thermal flow shocks (DT400 twin shock) - ideally in chrome (or nickel!).
Aftermarket chroming of springs seems a bit of a gamble…

 

I wonder if Ikon or Hagon would supply just the springs.

Phil, my mates brother owns this plating shop in Maidenhead www.chingfordtec.co.uk/
I have been meaning to pop over to see him and ask if he's interested in Nickel plating a few bits for me, these might include the springs off my CT1-B and my CT3.
I'll let you know how I get on.

I would agree that the springs are nickel as the finish rusts at the site of a rain cloud.
I bright nickel my springs and the finish is at least as good as theirs and in some cases lasts longer.
Did the whole lot on my HT1B. Not only that, i live in the UK too.
However i fitted a pair of Showa shocks from the states on that So you can do it at home.
Or you can get in touch with Allenchrome who do excellent work and they will do your springs dull shine. Not the cheapest but their work is bang on.
Ted

I think the reason why the OEM springs don´t look very shiny is they have been chromed as the are after winding process. Yamaha didn´t include polishing in the production flow, maybe just pickling  before plating, so surface of the spring wire was quite rough. .
Copper, Nickel and Chrome does not compensate the roughness.
 

Just to elaborate on MarkT’s comment on baking.

The heat will definitely take the tension out of the spring. I sent my classic car off to be acid dipped, they baked it first and I forgot to remove the tension bars in the boot/trunk attached to the hinges, now it won’t stay open