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520 chain conversion?

19K views 34 replies 14 participants last post by  justinlself  
#1 ·
Anyone do a 520 chain conversion? Seems with an alloy rear sprocket a bit of weight might be saved. Brands? Experiences?
Did a simmilar deal on my SV650 and saved a pound or so.
thanks,
-Armen
 
#3 · (Edited)
In theory you'd be reducing the robustness of your final drive, but that can be avoided by selecting a quality 520 chain with a high tensile strength figure.

Advantages of reducing chain and sprocket weight include the reduction of both unsprung and rotating weight, so it has the same effect as increasing an engine’s torque output, that is, it makes it easier to accelerate the bike and also gives the rear suspension an easier life.

If you look at this chart you'll see under "premium xw ring chains" a 520 size with very nearly the same tensile strength as the 525 in the same range and considerably higher than lower quality ones further up the chart.
 
#5 ·
Reasons

As for the waste of time and money arguement, consider this-when I did the same conversion on my SV650 (with alumium sprocket) it saved 1-1/2 lbs of mostly unsprung weight. Most racers and serious street/track riders would give their left nut for that kind of reduction. Whats more, the aftermarket parts were about half the cost of the OEM stuff.
I guess I should start my posts with "I'm not asking permission or telling you you have to do this."
As was pointed out, the high end 520 chains are more than strong enough.
While I was at it on the SV, I made aluminum wheel spacers to replace the steel stuff, bought a wave rotor (only $125 with new pads), and swapped to a lighter tire (Michelin Pilot Power). Net savings-over 4 1/2 lbs for not much cost. Rear suspension definitely tracked better.
 
#7 ·
did you do 2D datarecording?


i bet there is no "feelable" difference...i made all that stuff on my 675 racebike...saving 1kg...there is no feelable difference from 525 to 520

on those twins nobody really needs it...or are you racing?


which chain did you use? i never saw a racingchain like DID ERV 3 for half the price like VM

maybe you go chainshopping @ your local triumph dealer...but then i have to say you didn´t do your homework
 
#8 ·
Stuff

Hey Rodburner,
How did you do the longer swingarm-and why?

Twinfan,
As I said 'compared to the OEM prices."
As for the weight difference, it all adds up. I got roughly 4 1/2 lbs off the rear wheel. Even my uncalibrated butt shock dyno could feel a difference.
Oh, did I mention I gun drilled the axle, used Ti nuts on the sprockets, gun drilled the sprocket studs, and widowed the brake caliper carrier? Not kidding.



Not sure why anyone would pass up on the chance to drop some ass end weight. Especially if the chain and sprockets need replacing.

Again, I'm not asking permission : )
 
#12 · (Edited)
520 Conversion weights

OK, too much time on my hands + machine shop in garage + rabid intolerance for bloat/weight/anything-not-titanium = A summer of lightening..., including a 520 conversion.

Here's the real numbers:

Front Vortex 17t 520 sprocket: 216g
Rear SuperSprox Stealth 43t 520 sprocket: 574g
JT Super Heavy Duty Gold x-ring 520/106 chain: 2017g

Stock

Front OEM 18t: 317g
Rear OEM 43t: 910g
Chain, 525/106: 1966g

386g saved. Ordered an RK HD Gold x-ring 520/106, should be in Thursday and will weigh that (hoping it's actually lighter than the stock 525 chain, UNLIKE the JT...). Thinking the JT is WAY over weight because of the "super heavy duty" and high tensile spec.

On to milling the crap out of the rear rotor...

PS. Everyone likes pics, here's the front so far (new EBC XC Contour rotor):

Image
 
#14 ·
If you have to replace your chain and sprockets anyway, why not? I always change it up a bit when tires etc. are kaput. I am looking at going to 520 when my drivetrain finally wears out, but the lighter sprockets will cost me $50 more so I may just stick with stock. BTW, I love the rotors! Fancy rotors are worth it sometimes, if only just for aesthetics.
 
#16 ·
I have done the 520 conversion with lightweight steel components.
http://www.triumphrat.net/air-coole...nical-talk/838554-520-chain-conversion-wave-rotors-and-full-bore-usa-tires.html

I have about 700 miles on my set up. There is definitely a SOP improvement in power. Its also noticeably quieter with less vibration then my worn 525 set up. I wouldn't trash a perfectly good 525 set up to convert to 520. The 520 chain conversion with steel sprockets costs the same as 525 set up. A free 1-2 HP for doing maintenance is a no brainer. If you think the 520 chain conversion is nonsense explain why Triumph went to it from 2015 on?

If you don't think it works don't buy it.
 
#18 · (Edited)
If you think the 520 chain conversion is nonsense explain why Triumph went to it from 2015 on?
Cost. Less metal = less cost.

That's it. That's the real world benefit. <--- that's the key - the REAL WORLD benefit.

GSXR600 - 525 chain
GSXR750 - 525 chain
CBR600RR - 525 chain
ZX6R - 525 chain

All I'm saying is, don't get too hung up on the hype and throw money at a placebo. You want the 520, by all means. But don't think you're REALLY picking anything up in the real world. That's all.
 
#19 ·
New chain, RK HD Gold Xring 520: 1684g

So weight saved over stock 525 (with complete conversion as-above, only with the RK instead of the JT chain): 1.58lb (719g)

When looking at HP/weight ratios, that's nothing to scoff at. Esp if you need to change chain anyway.

And the bikes that run 525 still have a helluva lot more HP and are a helluva lot lighter than the Triumph. If the HP of the Triumph was too much for 520 chain, the factory wouldn't have gone to them. Basically, the 525 was overkill to begin with (and 1.5 of unnecessary weight). At least for the HP/weight of the bike.
 
#23 ·
Over 4000 people have viewed this thread...obviously there is an interest. Lets try to be objective here. Does ANYONE out there have a definitive dyno run of a Bonneville with 520 conversion? It would be interested to hear feedback from other who have actually done the conversion positive or negative.
 
#24 ·
Unfortunately, a dyno run won't tell the HP/weight ratio differences. It's shedding weight that I'm concerned with, not a net gain of HP, but a net loss of weight, which, with all else being equal, equates to higher HP/weight ratio.

As I've said before, if titanium bolts will net lower weight/higher HP/weight ratio..., then dammit..., it's tit bolts!
 
#25 ·
The theory behind going to a lighter chain/sprockets is that the reduced rotating weight will enhance throttle response and reduce parasitic power loss between the engine and the rear wheel, so a dyno test would tell you if this was the case or not, because it is run off the rear wheel. You could maximize these effects by also installing a lighter tire, or shaving some material off the rear wheel, or using lighter gauge spokes, or going to a radial spoke pattern on the non-drive side. Ideally, with the 520 chain/sprockets, a dyno test would show a faster rise in rpm at any given throttle setting, and a slight increase in power at any given rpm. Is this actually palpable on the road? Some say yes, others don't.
 
#26 ·
The theory behind going to a lighter chain/sprockets is that the reduced rotating weight...
Correct. To maximize the benefit, I went to a 17 front sprocket and 41 rear sprocket to keep sprocket diameters small/minimize the weight of the setup. If I wanted taller gearing, then I would have shed even more weight. Yeah, I can't keep the front wheel on the ground now due to the improvement... ;)

In my case I went with steel sprockets for durability. I've put over 10K miles on my set thus far and it still looks new. Old CBR600s that put out 90+ RWHP were fine with this size chain and so will anyone riding a 904 or smaller bonnie. If you're changing out your chain and sprocket, there's no reason NOT to go 520.
 
#28 ·
Follow up

Recent weight loss regime: Front EBC Vee Rotor (~1lb shaved), center drill front/rear rotor bolts (2g's off each bolt, 20g's total shaved), rear Galfer wave rotor (~3/4lb shaved), 520 chain conversion (~2lbs shaved).

Very noticeable felt difference in handling or "flickability" in corners. Feels like a different bike. These were the only things done this go-round, so I have to attribute the weight loss to it's felt increase in side-to-side cornering quickness (S-curve changeup). As far as any other increase in performance, I can't say I feel it. "Might" feel "less sluggish" though, so that's probably the seat of the pants felt change in accel.

One huge benefit with braking though, the front with the Pretech 6-pot, feels little changed from the stock disc, the rear, OTOH, actually feels like a brake now! Seriously, the rear was rusty and cobwebbed for total lack of use. Because it was useless. Locking it up in my dirt driveway was a rarity. Now it actually does something and slows the bike. I can lock it up on tarmac (would have to stand on it before) and easily do so in dirt now. That was something I did NOT expect (that a simple disc change would make such a difference in braking efficiency).

If I had to do all over again, the rear disc would be the first thing and considered MANDATORY, the rest, maybe not so much.
 
#30 ·
Increased flickability probably has a lot to do with the lighter rotors reducing weight on the wheels themselves, since the gyroscopic effect that keeps the bike upright and rolling in a straight line would be reduced too. Have you looked at lighter or even slightly smaller tires, like a 120/70 on the rear? I bet you could save 2-3 lbs. per tire, maybe more, by choosing carefully. A smaller rear would increase engine rpm vs road speed, potentially increasing acceleration, but maybe reducing top speed. Too bad you don't have a mag wheel Bonnie. I bet you could Dremel off a pound or two per wheel, maybe even more.
 
#31 ·
Right you are. But..., my initial thinking was that the small diameter of the disc would have minimal gyro effect as the closer to the axle weight is, the less effect it would have. Surprised that this has that much effect.

And running a narrower tyre isn't for me, so I'll stick with it as-is (150 rear, currently)
 
#33 ·
To be objective, I rather liked the Avon 140 I put on the rear of the last Thrux. 4k miles it kept its profile (mostly) and I never rode it to its edge. The Michelin Pilot Rd III I have on now (150/70) has almost ridden off itself, no more to go, worn out to the edge and I do hang off to keep from insane lean angles, so in the interest of safety (always thinking safety here), I'll probably go back to the Avon's at 140 once the Michelin's are done. I think the Mich is too "flat" of a profile for me anyway. Very predictable slide though, esp. in the rain (what they're known for).