Rider sag cold vs hot stock rear

[RoninJames]

Ok, so the debate has been does the heat from the exhaust affect the rear shock.

I needed to check my rider sag anyway so i decided to do a before and after. w my trusty 12 yr old assistant (my son) on the measuring tape heres the results.

Now, let me start by saying i weigh 185lbs. I had upped the stock shock setting to 7 and it was still a bit mushy and bouncy, so I upped it to 8.

At 8 there is ZERO free sag. yes its pretty stiff in that respect. But once i put my fat a$$ on it my rider sag COLD was about 26mm.

I took the bike for abot a 30-40 minute ride and came back and did it again and wound up with rider sag HOT of 33mm

so take what you will from my "science". maybe the oil was hot and gave more, maybe the spring was warm and gave more? either way after a short ride there was a 7mm difference. not huge. but the real issue is the lack of rebound damping so it def feels like when hot the rear shock bounces back up pretty quickly.

Now i am not a suspension specialist by any means so if some of the more technical guys in here wanna interpret my numbers please do, by all means.
Thanks

 

[mr-fabricator]

Sag is indicative if the spring not the viscosity of the oil in the shock so it shouldnt make any difference .

Im sure heat in the spring wont make any difference either otherwise they would all be deformed after a few heat cycles and years of use .

??????

 

[RoninJames]

so what do you attribute the 7mm difference to?
maybe my sons measuring skills are not precise? lol

so what is the deal with people saying the heat from the exhaust affects the oil making the shock mushy?

 

[mr-fabricator]

U get stiction in all suspension so take a few measurements and find the average , was the bike measured on flat ground ? Preferably exactly where it was placed the first time .

Hot oil is thinner than cold oil and thus it flows quicker , having a hot shock is like having thinner oil inside , my old TL1000r had a hugger on the back ( after market ) and handled badly , a guy in a car park said to take the hugger off , shock got more air flow and stayed cooler , was a lot better .

At the end of the day does the bike handle well and are you happy ? Sag is a very very rough set up from wich point u continue to tune .

i have my forks set down in the clamps 4 mm , many others here have them raised , i sit forward on the bike and realy give the front a hard time , if u sit further back and are a smoothe rider you can run the front nose down for a quicker turn in but your smoothe riding doesnt push the front as hard .

advising anyone in these matters are strictly ball park , only u know how u feel on the bike . I am myself palying with spring weights so asking outher users their weight and use , i will order springs frommthis but if they dont work for me i need to work from that proverbial start point .

Welcome to the world of suspension and all the greif it will bring happy days .

 

[RoninJames]

U get stiction in all suspension so take a few measurements and find the average , was the bike measured on flat ground ? Preferably exactly where it was placed the first time .

Hot oil is thinner than cold oil and thus it flows quicker , having a hot shock is like having thinner oil inside , my old TL1000r had a hugger on the back ( after market ) and handled badly , a guy in a car park said to take the hugger off , shock got more air flow and stayed cooler , was a lot better .

At the end of the day does the bike handle well and are you happy ? Sag is a very very rough set up from wich point u continue to tune .

i have my forks set down in the clamps 4 mm , many others here have them raised , i sit forward on the bike and realy give the front a hard time , if u sit further back and are a smoothe rider you can run the front nose down for a quicker turn in but your smoothe riding doesnt push the front as hard .

advising anyone in these matters are strictly ball park , only u know how u feel on the bike . I am myself palying with spring weights so asking outher users their weight and use , i will order springs frommthis but if they dont work for me i need to work from that proverbial start point .

Welcome to the world of suspension and all the greif it will bring happy days .

hahahah thanks Lee, for me the rear def feels stiff but the 7th setting was too mushy. i just bought an 02 R6 ohlins shock after the tests that matt and you guys have been doing in the other thread. knowing it fits and has ride height adjustment and rebound damping will def help. also the ohlins has a threaded adjuster so i should be able to dial it in much better.

 

[Bagwell]

I was watching that shock pretty hard. They lowered the price and it finally sold.

 

[mr-fabricator]

Hope u got it for a good price , ohlins Ttx are renouned for being a little soft but our bikes are so light that will be a good thing , my street bike needs stiffness so TTX isnt an iption and i know a few triumph daytona boys who swap them out . My R6 2008 race bike has K Tech front and ohlins rear , it hooks up pretty good and they work very well together . Again this is where we will all have different preferences .