xbr 500

[guest1826]

recently bought an xbr 500, want to replace the front fork springs, anyone know where to buy new or preferably 2nd hand, and/or wat other forks would suit, cheers all

[SteveC#222]

The only alternative springs I know of are Hagons Progessives about £80 from Wemoto.com.  I had some and didn't like them, they are longer than the standard springs but when fitted they feel really soft , but as they are longer you can't fit the standard spacer to stiffen them up.

The standard fork springs ( and for that matter the rear shocks) are suprising good and long lasting for OE Honda - ( my rear shocks are about 20 years old and still OK).  If the standard springs are within service limits - minimum 428mm - the best thing is to fit an extra 1/2" spacer to stiffen them up a bit.  You can also lower the front end slightly by lifting the forks up 1" through the yokes to steepen the steering angle - this sharpens up the steering quite nicely.

[guest1826]

new to site, ta v much for help

[guest1733]

I was just about to ask the same question so thanks from me as well.

[Propellor]

The initial rate of the hagon is lower than the std Honda spring on lower free length limit?

What is meant by spring stiffness?

[Moto63]

Hi all,
I run my XBR cafe racer with hagon progressive springs at the front and find them pretty good, the bike has been stripped back quite a bit so has lost a few kilos . I also have a pair of hagon fully adjustable shocks at the rear but find them over sprung even on the softest settings. Pair of maxtons are on the shopping list

[guest564]

I run Progressive Suspension springs that were designed for an SRX600, I had to cut down the stock spacers to suit. The PS springs are a little stiffer on both initial and final rate but I found that the stock springs were bottoming out with upgraded brakes and stickier tyres even though I was running 12mm of additional spacers. At the time no one was selling springs for an XBR.

Edit: I had the forks lifted 25mm through the yokes so they may not have been bottoming out but the front mudguard/fork brace was hitting the bottom yoke.

[guest564]

I found an article that I wrote a while back, apparently I spoke to PS direct, I know I spoke to MR Holland regarding the rear Konis.

I couldn't source any replacement springs specifically for the XBR500. However I read in a number of places that the GB500 was a little stiffer sprung than the XBR. Contacting Progressive Suspension I learnt that the diameter of the GB springs was different to those of the XBR. Their catalogue did however furnish the information that the uprated springs for the GB were rated at 30-40 lbs/in. After providing then with the diameter and length of the stock spring they suggested their replacements for the Yamaha SRX600, these were the correct diameter with a rating of 30-45lbs/in. These seemed perfect as the harder rate at full compression would help reduce the amount of dive caused by the bigger front brake set up. The specs I have I'm reading off the back of an 8 year old envelope, Part Number I have for the Progressive Suspension springs is 11-1128, dimensions are 502mm, 29mm OD.
The spacers provided with the SRX springs were the wrong length for the XBR so I followed Progressive's advice and cut them down such that the springs extended 10mm above the top of the stanchions with the forks fully extended. Fork oil was added as per the Honda manual but 12.5W oil was used to give a little extra damping to match the springs. The result was much less dive under braking giving better stability, and with less weight transfer to the front much less of a tendancy to lift the rear tyre off the ground.
The front forks were lifted through the yokes around 25mm, quite a lot but in standard trim the steering is very slow indeed.


Edited to correct units of force.

[Propellor]

I run Progressive Suspension springs that were designed for an SRX600, I had to cut down the stock spacers to suit. The PS springs are a little stiffer on both initial and final rate but I found that the stock springs were bottoming out with upgraded brakes and stickier tyres even though I was running 12mm of additional spacers. At the time no one was selling springs for an XBR.

Edit: I had the forks lifted 25mm through the yokes so they may not have been bottoming out but the front mudguard/fork brace was hitting the bottom yoke.

Hi rhinoman.

Maybe the bottoming out in spite of extra spacers can be explained by the fact that spacers set preload and suspension sag but don't (can't) affect spring rate? A "soft" spring is soft no matter how many spacers are applied, no? The position the forks end up under heavy braking surely will be determined by the reaction into the forks under braking. For any given reaction (edit: and any given spring rate) won't this compress the springs to the same point to equal this force every time? Regardless of the number of spacers (amount of preload). Unless the force is less than the preload force, in which case no movement will occur at all.

[Propellor]

I don't know if the hagon fork springs are a higher rate or lower rate than the std fit honda ones, but here are the hagon basic parameters for their progressive xbr500 springs, for anyone considering them:

Diameter  28.40mm
Length 533mm
Rating  4.00kg/cm < 7.50kg/cm


If anyone knows the honda data perhaps they could post the info for comparison?

Cheers.

[guest564]

Are you sure about that? that equates to 57 lb/sq in -> 107lb/sq in, that would be rock hard.

[guest564]

Maybe the bottoming out in spite of extra spacers can be explained by the fact that spacers set preload and suspension sag but don't (can't) affect spring rate? A "soft" spring is soft no matter how many spacers are applied, no? The position the forks end up under heavy braking surely will be determined by the reaction into the forks under braking. For any given reaction (edit: and any given spring rate) won't this compress the springs to the same point to equal this force every time? Regardless of the number of spacers (amount of preload). Unless the force is less than the preload force, in which case no movement will occur at all.

Pretty much but if the springs are ie 35lb/in then you need another 70lbs of force to overcome the effect of the spacers.


Edited to correct units of force

[Propellor]

Maybe the bottoming out in spite of extra spacers can be explained by the fact that spacers set preload and suspension sag but don't (can't) affect spring rate? A "soft" spring is soft no matter how many spacers are applied, no? The position the forks end up under heavy braking surely will be determined by the reaction into the forks under braking. For any given reaction (edit: and any given spring rate) won't this compress the springs to the same point to equal this force every time? Regardless of the number of spacers (amount of preload). Unless the force is less than the preload force, in which case no movement will occur at all.

Pretty much but if the springs are ie 35lb/sq in then you need another 70lbs of force to overcome the effect of the spacers.

Hi

I'm not sure about your actual figures, but my point anyway was that if your springs were bottoming for a given braking reaction force, then the same spring will bottom for the same braking reaction force regardless of spacers. To stop it you'd have to spacer the thing to coil bound!

That's my interpretation of things at any rate (pun).

Cheers

[Propellor]

Are you sure about that? that equates to 57 lb/sq in -> 107lb/sq in, that would be rock hard.

The figures are direct from hagon, who answered my e mail within an hour on Saturday morning.

I'm not following why you are quoting a psi figure? Surely the rate is expressed as pounds, or kg or N etc per inch or cm. not sq in or sq cm?

By my approximation the rate converts to about 25 lb/in to 45 lb/in. Maybe a tad higher. Does that sound about what you'd expect?

It's difficult to convert as the spring rate isn't constant and I don't know the rate of rise.

Cheers

[guest564]

Must have been the beer, I had the units wrong when I wrote that years ago. So 25-> 45 lbs/in sounds about right.