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Sam.moz86
Premium Member Joined: 18 Jan 2017 Location: Cardiff Status: Offline Points: 481 |
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Posted: 03 Jul 2019 at 11:01 |
Been a while since I've posted but I'm in need of advice and help.
I've started to track the gen 2, suspension feels great in every aspect other than braking. I'm bottoming out, I've set the Sag, I've plaid with compression and still can't stop it. Any harder and it's going to compromise corner feel. Is there a way of telling what weight the current springs are rated for, and is there somewhere I can buy springs to suit my weight? I've had the rear shock serviced and a spring to suit and it's spot on. Cheers.
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blacklines
Moto GP Alien Joined: 08 Jan 2018 Location: Yorkshire Status: Offline Points: 1060 |
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Compression will change the speed of fork dive and will prevent bottoming on short sharp bumps but over the course of a braking area and corner it's the spring that's supporting you. Assuming you don't have the compression wide open I'd start with the fork springs. The stock springs on my gen 1 Showa forks don't have the rate stamped on them but I believe most aftermarket ones do. You could have a look and if there's no rate numbered on the springs then you may be on stock. Failing that, most suspension specialists can measure the rate of springs. Or you could do it yourself to a very rough accuracy but it would be a right faff involving a balance (or bathroom scales), some means of compressing the spring and a ruler. Best bet would be to contact a suspension shop, let them know your weight and pace/group and they'll send you what they think is right. At least then for about £85 you'll have a known starting point. How much do you weigh? I'm about 16 and a half stone and can run decent sag numbers while still leaving about 10mm travel in reserve. Possibly my springs have been upgraded but like you I have no idea what rate they are. I did have to uprate the shock spring a fair bit though to 105N/mm but it now seems to match the front. So I assume I have 100 in the front.
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roboxm3
Moto2 racer Joined: 28 Mar 2013 Location: Cambs Status: Offline Points: 112 |
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I'm not sure if it's the case for Gen 2 bikes but I'm sure that the Gen 1 manual has details of factory spring rates, so it could be worth checking there and do a bit of reading up as to how suited or not they are for your weight.
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Spoonz
Admins Group Joined: 11 Feb 2008 Location: North Devon Status: Offline Points: 10726 |
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The oem springs are not progressive so the rising rate is mostly from the oil level. Compression damping will slow how quickly it bottoms but on long braking efforts it will still bottom and you may upset the overall feel. If you run stiffer springs it may solve your bottoming problem but will affect 100% of the travel. Spring rate should be based on your sag to preload ratio more than anything else. If you don’t need lots of preload to get the correct rider sag then your springs are likely fine.
If you reduce the air gap you affect the rising rate in particular the last 1/3 of travel. That’s where I would go in 5mm or 10mm increments depending on how hard it bottoms. It will have almost zero effect on the rest of the travel if your happy that is fine.
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Sam.moz86
Premium Member Joined: 18 Jan 2017 Location: Cardiff Status: Offline Points: 481 |
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Thanks for the replies Gents,
I'm thinking from a starting point a new set of springs. With regards to the air gap Spoonz, so making the air gap bigger could potentially help? If i remember i'm currently running a standard gap (85mm) roughy from memory. Brooks suspension seem to offer Ktech internals for around £85 so i may give the a shout and see what they charge for a complete rebuild. JHS rebuilt my rear shock last winter but I can't say their service was incredible.
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Spoonz
Admins Group Joined: 11 Feb 2008 Location: North Devon Status: Offline Points: 10726 |
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Less air gap means faster rising rate and vice versa. So you would need to go to 80 from 85 if you want to ramp up the bottom of the travel. I had the opposite problem to you and ran a 90mm air gap based on springs in and damper rod raised. All above assumes they are ohlins.
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blacklines
Moto GP Alien Joined: 08 Jan 2018 Location: Yorkshire Status: Offline Points: 1060 |
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By Ktech internals you mean springs right? Because I think their piston kits are £240+ and cartridge kits even more.
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IanG
Premium Member Joined: 04 Oct 2010 Location: N Wales Status: Offline Points: 10725 |
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If we're talking Showa's then ideally the adjusters need changing as well as the valving. Stock showa adjusters are shaped with an abrupt taper and are effectively wide open after about a turn, anything outside that is only doing something in your mind unless you're using treacle instead of oil. Having ohlins isn't a universal answer either, one of my mates complained about the crap ohlins fitted to his 1098s and found they were so far out of the ball park as standard for most riders that both the springs and all internals were ditched by those in the know ( and had very deep pockets) for Ktec. Forgot about the initial question It's my understanding that if you can achieve both the excepted static and rider sag figures then that spring is correct for you. In my case, (gen2 Tuono showa) , if I set the rider sag correct I have so much preload the static sag is minimal I believe this tell me two (possibly 3) things a) I'm a fat bloater that needs to shed 3 or 4 stone b) I need stiffer springs and c) I miscalculated when I re vamped the compression shim stack or on the oil viscosity used |
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www.apworkshops.co.uk
www.apriliaforum.co.uk www.apriliaownersclub.co.uk Looking forward to the next track day |
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blacklines
Moto GP Alien Joined: 08 Jan 2018 Location: Yorkshire Status: Offline Points: 1060 |
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Yeah what I'd heard is that the Ohlins at least have much better adjusters, even if they don't perform any better and are prone to leaking seals. Like you say, with the Showas you're squatting by the fork leg trying to make the tiniest turns of the adjuster screw. Same with the rebound really, except that's just a crack open from shut for me. You have the Factory with Ohlins though don't you Sam? Think Spoonz hit the nail on the head with the air gap. It it's fine everywhere else then a smaller air gap will stiffen up the last portion of the travel. If you're not going to rebuild the forks at the same time you could always just unscrew the caps and tip a very small amount of oil into each leg couldn't you. Give it a go then add more if it's going in the right direction but not enough.
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IanG
Premium Member Joined: 04 Oct 2010 Location: N Wales Status: Offline Points: 10725 |
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Replacing the std ohlins adjusters with Ktec made a great difference to my mates 1098. I remember seeing them in the pack before they were fitted and thinking 'they look really nice but you don' t get much for your money these days' but he was really pleased with the finished units. So knowing that it's not difficult to appreciate just how poor the over the counter stock forks are, showa and ohlins. Funny that most people want to spend money on cans or go faster toys and don't have a clue how atrocious their suspension really is. Almost like cart springs compared with an double wishbone set up on a car. Good idea about just adding some oil though
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www.apworkshops.co.uk
www.apriliaforum.co.uk www.apriliaownersclub.co.uk Looking forward to the next track day |
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david000
Moto2 racer Joined: 09 Nov 2018 Status: Offline Points: 102 |
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Does having the ohlins serviced make much improvement, or is it a design issue ? With the newer bikes mentioned it sounds like a design problem.
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blacklines
Moto GP Alien Joined: 08 Jan 2018 Location: Yorkshire Status: Offline Points: 1060 |
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Are you talking about electronic suspension David? Is what a design issue?
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Owen
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david000
Moto2 racer Joined: 09 Nov 2018 Status: Offline Points: 102 |
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blacklines - sorry I may have miss interpreted the thread, where IanG said "Having ohlins isn't a universal answer either, one of my mates
complained about the crap ohlins fitted to his 1098s and found they were
so far out of the ball park as standard for most riders that both the
springs and all internals were ditched by those in the know ( and had
very deep pockets) for Ktec. " I assumed it was standard suspension, and on reflection that was likely a newer bike rather than an old one in need of TLC. I have ohlins on my early Factory and pondering having the shock serviced, hence the question. |
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blacklines
Moto GP Alien Joined: 08 Jan 2018 Location: Yorkshire Status: Offline Points: 1060 |
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Think Ian was meaning that a lot of people go "it's got Ohlins it must be good". But there's Ohlins and then there's Ohlins. And there are many competitors that perform just as well, or better. It's a very strong brand like Brembo is for brakes but that doesn't necessarily make it the best option. In the case of the 1098s it looks like it was also a design problem. In that the springs were wrong and the valving was wrong for most people. Or I think that's what Ian was saying. Getting it specced right for the application is within reason more important than the quality of parts. So long as the fork tubes don't flex and go up and down with minimum friction it doesn't matter whether they are black Showa or gold Ohlins. So long as the adjusters give good control like Ohlins tend to and not all in the first turn like gen 1 Showas then it doesn't matter too much outside of racing. Then it's just get the right spring rate for the rider and get the right valving for the spring and rider. I say just but the damping in particular is a very complex thing to get right and is responsible for the feel of the forks. It's probably due for a service that shock if it hasn't had one in the last few years. It should make a noticeable improvement for the money, but won't change the bike. Haven't done my Sachs shock yet but when I serviced the forks they did feel better after.
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Owen
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IanG
Premium Member Joined: 04 Oct 2010 Location: N Wales Status: Offline Points: 10725 |
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Yup, that's exactly what I meant. The name itself isn't always a given it will work well. I think the 1098s I used as an example was probably just Ducati buying a set of forks off the the shelf and hoping they worked. They possibly did for a skinny midget, but most normal people would see major improvements with some mods. I've been in Maxton's and seen a room full of Ohlins forks, some taken off bikes that came straight from the showroom as the owners knew how far off the specs were as supplied.
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www.apworkshops.co.uk
www.apriliaforum.co.uk www.apriliaownersclub.co.uk Looking forward to the next track day |
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legend88
Premium Member Joined: 18 Aug 2013 Location: Newcastle Status: Offline Points: 6598 |
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It's just proof that with a bike where rider weight is a significant part of the overall weight (Unlike cars) often around 30% or more, it's impossible to make a showroom spec bike suit everyone. Unless you are lucky and it does suit your weight, you either accept the compromises - as many do, often knowing no better - or you spend the money making it suit you. Even then it still needs setting up and how many people that have adjustable suspension ever touch it? The manufacturers could allow you to spec up springs and stuff but with the relatively low volumes they produce this would probably be more expensive than getting aftermarket stuff as anything in the OE chain is ludicrously priced. |
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dog78
Premium Member Joined: 18 Jan 2015 Location: Winchester UK Status: Offline Points: 1508 |
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Take to Darren at MCT, you probably have to wait 3 months. I have a Maxton on the rear which I bought second hand and sent to Maxton for a rebuild and revalve for my weight, the tyre wear was perfect and the difference between the the oem Ohlins was night and day. But Darren at MCT says that that shock on the gen2 had a problem and he could have sorted it out save me buying a Maxton.
Suspension is not a black art but the variations are vast, the setup is crucial, MCT set up the 2015 R1 Superstock, it has his personal Ohlins forks with the Ohlins GP shock, and the suspension is perfection. Quaiilty parts and a great setup worth its money all day long. It has to be setup for your weight and use, the Superstock still has an mot and I have took it on the road but it is far too hard, but it was what I asked for and at Almeria it was perfect, it has 100spring in the rear and 10s as fork springs for a 12.5 stone rider kitted out. For the rsv Maxton do a big piston fork conversion or I might just gave revaled and sprung. Tbh the front on the rsv is great since it had Ohlins fork oil in it which made it noticeably stiffer. Both bikes are totally different from what they were, the above makes a world of difference.
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