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Why is mx tech spring rate calculator telling me i dont need heavier springs?


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I just got a 2007 crf 250r i weigh 195 without gear and from what i understand that year is valved softer already. The first thing i felt on the bike was that it felt too soft. Actually i was thinking to myself this set up would be great off road lol. I have my reboud at 6 and compression at 6.

I went on mx tech site to use the calculator, i put in 205 and 210 pds and its telling me to go one heavier on the shock, but do nothing on the forks. Im not a experet but this cant be right. Whats the deal?

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2007 Honda CR250R

Type of Riding: Motocross

Rider Weight: 195 lbs

FRONT FORK SPRINGS

Recommended Fork Spring Rate: 0.463 kg/mm (use closest available)

Stock Fork Spring Rate: .430 kg/mm (stock)

REAR SHOCK SPRING

Recommended Rear Shock Spring Rate: 5.08 kg/mm (use closest available)

Stock Shock Spring Rate: 5.0 kg/mm (stock)

http://www.racetech.com/

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2007 Honda CR250R

Type of Riding: Motocross

Rider Weight: 195 lbs

FRONT FORK SPRINGS

Recommended Fork Spring Rate: 0.463 kg/mm (use closest available)

Stock Fork Spring Rate: .430 kg/mm (stock)

REAR SHOCK SPRING

Recommended Rear Shock Spring Rate: 5.08 kg/mm (use closest available)

Stock Shock Spring Rate: 5.0 kg/mm (stock)

http://www.racetech.com/

That's for a cr not a crf.

You will do good with a .46-.47 front and 5.4-5.5 rear. A set of stock crf450r springs would work also.

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2007 Honda CRF250R

Type of Riding: Motocross

Rider Weight: 195 lbs

FRONT FORK SPRINGS

Recommended Fork Spring Rate: 0.467 kg/mm (use closest available)

Stock Fork Spring Rate: .450 kg/mm (stock)

Available FRSP 4349 Series Springs are:

REAR SHOCK SPRING

Recommended Rear Shock Spring Rate: 5.28 kg/mm (use closest available)

Stock Shock Spring Rate: 5.2 kg/mm (stock)

Available SRSP 6727 Series Springs are:

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ok never mind i finally found the stupid calcualtor. Well It looks like i can bump up on th eforks one but maybe keep the spring on the shock stock. I am in between really according to this but i know my sag cant be set right in the rear so i have to bump that up also i guess

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ok never mind i finally found the stupid calcualtor. Well It looks like i can bump up on th eforks one but maybe keep the spring on the shock stock. I am in between really according to this but i know my sag cant be set right in the rear so i have to bump that up also i guess

And here I thought I was the only one that thought that the navigation on Race Tech's website sucked azz. 👍 I found their calculator by accident and then couldn't find it again for like 3 days. :blah:

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I think both sites calculators are wrong , both of them give the wrong stock rates for my 450R and 450X , they are both completely different from what the manual and parts fiche say is correct STOCK spring rates , i guess its only useful if you use their springs and believe that they know something about the factory spring rates that the factory does not , as that could be the only explination as to why they are both different from each other and the factory

I still have no clue as to what springs i actually need for my bikes for my weight (195 without gear or shoes 200 in street clothes) after looking at both calculators

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2007 Honda CR250R

Type of Riding: Motocross

Rider Weight: 195 lbs

FRONT FORK SPRINGS

Recommended Fork Spring Rate: 0.463 kg/mm (use closest available)

Stock Fork Spring Rate: .430 kg/mm (stock)

REAR SHOCK SPRING

Recommended Rear Shock Spring Rate: 5.08 kg/mm (use closest available)

Stock Shock Spring Rate: 5.0 kg/mm (stock)

http://www.racetech.com/

Race-tech recommends front fork springs too stiff for me @ 225lbs on a 2009 YZ450F. I run a .48 and they recommend a .50

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lol oh thats great. Does race tech have a calculator? I cant find it on that horrible web site they have

there always off for me as well......usually on the soft side

i always call like 3-4 co.....fc,pc,rg3 to get an idea of what rate i need if i dont know or am on the fence...........fc is on the soft side, rg3 is usually on the stiff side and pc is usually right in the middle or equal to rg3...........

there are almost always at least 2 spring rates for every rider depending on how you like your bike to ride......some like it stiffer and some like it on the softer side

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Race-tech recommends front fork springs too stiff for me @ 225lbs on a 2009 YZ450F. I run a .48 and they recommend a .50

.48 fork springs for a 225lb rider is on the soft side. Stock is .47 and is good for a 175-185lb rider. I would have to side with racetech on that one and that's a first!

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I just got a 2007 crf 250r i weigh 195 without gear and from what i understand that year is valved softer already. The first thing i felt on the bike was that it felt too soft. Actually i was thinking to myself this set up would be great off road lol. I have my reboud at 6 and compression at 6.

I went on mx tech site to use the calculator, i put in 205 and 210 pds and its telling me to go one heavier on the shock, but do nothing on the forks. Im not a experet but this cant be right. Whats the deal?

Well, when I entered your weight (+20 pounds for gear) into the MX-Tech calculator for a 2007 CRF250, it told me that you needed a .46kg fork spring and a 5.4kg shock spring. Stock on that bike is a .45kg fork spring and a 5.3kg shock spring. Personally, I think the result is a little light for a 215# rider. I would suggest that you run the 450 spring rates. .47kg fork springs and a 5.5kg shock spring.

Someone posted that our rates are "always wrong" and that we think we know something that the manufacturer doesn't. A couple of points to remember: #1, the majority of the rates we enter into our matrix are from at least one of two sources - shop manuals or factory build sheets. If you know a more accurate way to find the rates, please let us know. #2, it is completely possible that sometimes we make a mistake in data entry. The spread sheet for this info on our web site is huge and it's also very tedious and time consuming to keep updated. Mistakes can happen. And #3 (and probably most important), if you don't think our calculator is giving you the correct info - CALL US! We'll be glad to go over what you need for your bike.

👍

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Thanks. Yeah my stock spring rates were listed correctly. I think there was a issue with the site cause I tried multiple time putting different weights in and was not getting changes but it was working this morning.

Now if I put a 5.5 spring on and 4.6 fork and say I lose five or ten pounds is that gonna make the bike feel real stiff cause I don't want that. Also I am not jumping anything big at all.

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