Kronos XTR Easiest way to adjust servo saver?

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Gatsou7 said:
Thanks Horatio, sign me up!
I'd be happy to try this out on my XTR.;)
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Right you are! Yours is booked.

I'm happy to sell them at cost (£3.30) plus shipping (not sure how much this will be yet - but it will be at cost, I'm not marking anything up).


@ anyone else interested. There are 5 more springs left only! 😁👍
 
It's a massive improvement over the stock spring! I'm actually very tempted to try out these other 3 springs, same dimensions but slightly lower compression rates.

LC 085J 0 S | LC 080J 0 M | LC 080J 0 S
Screenshot at Jun 29 10-57-27.webp


I've only ran a couple of packs since I installed LC 085J 0 M but I'm happy with it. It's much stiffer than the stock one, but not as bad as tightening the servo saver completely, but I want to play around with lower rates to see how they compare and to figure out if there's a better sweet spot where you can turn at high speeds while providing the maximum protection to the servo, finding that balance. But I won't be able to do this until mid August with holidays and all that coming up.
 
DaniC said:
It's a massive improvement over the stock spring! I'm actually very tempted to try out these other 3 springs, same dimensions but slightly lower compression rates.

LC 085J 0 S | LC 080J 0 M | LC 080J 0 S
View attachment 2608

I've only ran a couple of packs since I installed LC 085J 0 M but I'm happy with it. It's much stiffer than the stock one, but not as bad as tightening the servo saver completely, but I want to play around with lower rates to see how they compare and to figure out if there's a better sweet spot where you can turn at high speeds while providing the maximum protection to the servo, finding that balance. But I won't be able to do this until mid August with holidays and all that coming up.
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Nice one! It might be worth a shot provided you don't mind Lee Spring's exorbitant admin fee.

I have the LC 085J 0 M springs in my hands now and it is definitely much firmer. Perfect for heavier, belted tyres - mine on the wheel, with hexs and steel screws weigh a whopping 441g per corner.

Just like you say Dani, the major advantage is that the spring still has some give in it - unlike the stock one clamped down, which is more or less locked.

I'll be doing the work this evening and putting a link in PM's to my ebay listing. 👍
 
So, all done, fitted - pretty much what Dani said, but I have a couple of points I'd like to add.

Here's what the stock item looked like, clamped up -

IMG_20220629_181723.jpg


The new springs are slightly bigger than stock, both in length and diameter. In my bag of 10, there is some degree of tolerance. At the bigger end of this spectrum, the spring is a firm interference fit - meaning it will need prying into the plastic servo saver arm with small screwdriver - but it will fit with effort.
IMG_20220629_182222.jpg

Stock spring can be fully compressed between finger and thumb! Good luck trying that with the upgraded spring - it ain't happening!

IMG_20220629_183525.jpg

Collar compresses the spring slightly before it meets the threads - this isn't a problem, but care is required to:

A) ensure that the collar is square to the thread

B) provide adequate force to act against the spring until at least the first 2-3 threads have got a purchase.

Failure to do this will likely result in stripping out the threads on collar and/or the post.

IMG_20220629_185103.jpg

Whilst I had the servo saver out of the car, I fettled the edge of the front gearbox where the input shaft bearing carrier is. This provides a better clearance for the ackerman plate which interferes at full left lock. This is more relevant now that the car is able to attain full lock with the improved action!
IMG_20220629_185209.jpg

You can clearly see in this shot where the steering assembly interferes with the front gearbox.

With the fettling done and the braces back in place, the steering was super free but with zero slop.
IMG_20220629_185247.jpg

During the assembly, I like to keep the screws in order using a divider and magnetic dish. Especially if the cat is helping me.

I have no doubt this mod will solve the centering issues and prevent wander, especially at high speed.

When I get to test run next, I'll see if I can beat 62mph. I'm sure I can get 70mph out of it.....

Edit to add:

Also reduced toe-out, which was close to 3°. It's now 1° which I believe will help with straight line stability.

Also: for sale, 1 stock spring, 1 careful lady owner from new....... 😜
 
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Horatio said:
So, all done, fitted - pretty much what Dani said, but I have a couple of points I'd like to add.

Here's what the stock item looked like, clamped up -

View attachment 2619

The new springs are slightly bigger than stock, both in length and diameter. In my bag of 10, there is some degree of tolerance. At the bigger end of this spectrum, the spring is a firm interference fit - meaning it will need prying into the plastic servo saver arm with small screwdriver - but it will fit with effort.
View attachment 2613
Stock spring can be fully compressed between finger and thumb! Good luck trying that with the upgraded spring - it ain't happening!

View attachment 2614
Collar compresses the spring slightly before it meets the threads - this isn't a problem, but care is required to:

A) ensure that the collar is square to the thread

B) provide adequate force to act against the spring until at least the first 2-3 threads have got a purchase.

Failure to do this will likely result in stripping out the threads on collar and/or the post.

View attachment 2615
Whilst I had the servo saver out of the car, I fettled the edge of the front gearbox where the input shaft bearing carrier is. This provides a better clearance for the ackerman plate which interferes at full left lock. This is more relevant now that the car is able to attain full lock with the improved action!
View attachment 2617
You can clearly see in this shot where the steering assembly interferes with the front gearbox.

With the fettling done and the braces back in place, the steering was super free but with zero slop. View attachment 2618
During the assembly, I like to keep the screws in order using a divider and magnetic dish. Especially if the cat is helping me.

I have no doubt this mod will solve the centering issues and prevent wander, especially at high speed.

When I get to test run next, I'll see if I can beat 62mph. I'm sure I can get 70mph out of it.....

Edit to add:

Also reduced toe-out, which was close to 3°. It's now 1° which I believe will help with straight line stability.

Also: for sale, 1 stock spring, 1 careful lady owner from new....... 😜
Click to expand...
Oh that's a great idea fleeting the gearbox like that, I'm definitely doing this! I agree everything is a very tight fit in that area, and in my case there's also some rubbing off the lower plate onto the input gear cup.
Also, you probably noticed there's a shim at the top of the shaft on the saver side. I was measuring and I think it would benefit from an extra shim on top on both sides, I think a 0.30mm should do. Otherwise you might notice that if the servo pushes the steering to one of the sides (can't remember which side) there's a bit of slop and it comes from the servo saver moving slightly up and down on the shaft.
 
DaniC said:
Oh that's a great idea fleeting the gearbox like that, I'm definitely doing this! I agree everything is a very tight fit in that area, and in my case there's also some rubbing off the lower plate onto the input gear cup.
Also, you probably noticed there's a shim at the top of the shaft on the saver side. I was measuring and I think it would benefit from an extra shim on top on both sides, I think a 0.30mm should do. Otherwise you might notice that if the servo pushes the steering to one of the sides (can't remember which side) there's a bit of slop and it comes from the servo saver moving slightly up and down on the shaft.
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Thanks for that tip. I'll check that. On mine, there were 2 small shims, one each side. They are now slightly magnetised and less likely to fall off during disassembly.

Whilst the steering is all nice, I think the top wishbones could benefit from shimming to remove slop, now the car is bedded in.

In fairness I've cained the car on full throttle runs and ragged it over a bumpy grass track. It's not been crashed yet, but on those tyres I'm using, that's a lot of traction and I'm guessing a fair amount of force on the steering and arms.

If it's wear creeping in, in addition to shims, longer term I'd like to find a way of fitting delrin bushes on the arms where the captive hinge pins pass through.
IMG_20220629_220742.webp
 
The listing has been updated to allow international buyers and has 2 more pictures. It's all legit 100% through PayPal and there's even a 14 day return! 🤣
 
Horatio said:
I'm not sure if it does to be honest - it's a fair bit smaller, so my guess would probably be no. People here are bound to know though.
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Well I compared the exploded view of the Sketer and the XTR and they seem to use the same parts around that area, the same springs too. So my guess it that it should fit fine.
 
DaniC said:
Looking at the exploded views side-by-side, yes they seem to use the same servo saver and same spring so it should fit just fine.

View attachment 2626
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Sorry - my reply was before this post was visible. According to these diagrams - it's the same part! No wonder this spring struggles with Kronos steering - especially with bigger tyres!
 
Guys - last 4 springs! 😁👍 Glad to have been of use to some of you here.

This will be the last chance to get them at cost - the smaller, weaker Arrma spring is £9.99 and isn't made from music wire either.

Revised listing with heading to include Skeeter and Shogun flavours are here:

Upgraded Spring for servo saver
 
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