powell rear spring

CarPlayLB

Well-Known Member
#2
I actually wound up using two springs. I found a nice chrome spring and it was too light...my 250lbs of fat A$$ would crush it, so I bought an inner spring that is heavy and now it supports my delicate backside well...here are a couple of links

heavy inner spring
Raymond Yellow Compression Die Spring 4" Long PN 206 516 | eBay

outer chrome spring
1 ea 1 565" OD x 236" Wire Dia x 4 150" Long Compression Springs Chrome | eBay

I had to cut about one coil off the inner to make everything fit together...it does not look factory fresh, but it sure works nice!

I also found a bicycle mono shock that I cut the ends off and rounded enough to fit in the cups...it had a 750lb rated spring and worked well, just didn't look right!
Good luck, hope this helps
 
#4
I realize this is an old thread, but I just spent awhile researching this, and ordering springs, so wanted to get the info posted for the next person looking for a spring.

Century Spring, (they are on line) part number 4115. (Century requires min. order of $50)

Max load is 478 LBS, and they are nearly identical to the original Powell spring I used as a measuring sample.

I also ordered two lighter springs. One that would work for those under 185 LBS, is max rated 292 LBS, and one lighter yet for a max weight of 257 LBS. (IE a 100 LB rider)
 

CarPlayLB

Well-Known Member
#5
Dave, thanks for posting that!
One concern of mine was the leverage factor with the swingarm. If the ratio is 3:1, would the 478lb spring truly support 159.33lbs at the rear axle? If that is the case, I'd still need a 750lb spring! I know that the rate increases as the spring is compressed.
If I recall, the wire diameter is close to 1/4". With the same amount of coils and the same diameter wire, is it possible to have different rate springs?
I would be interested to see how it works on the bike with one of us old fat guys on it!
 
#6
I just installed it with the bare frame and swing arm. So far, so good. My 240 LBS couldn't come close to bottoming it out, but a complete frame is a better test.

I also tested their 4259 spring. It is way softer and has more travel. I suspect that spring is too weak for a 200-plus pound rider, but that is a guess.

I have another spring 72929 coming in which is between both of the above springs with regard to max. load recommendation.
 
#8
Guys another trick is to pack the inside of the spring with shock rubbers . My stock spring would bottom at just the slightest bump , now with it filled solid it's prefect no bottoming and seems to have some compression feeling .
 

6doggie3

Well-Known Member
#10
Guys another trick is to pack the inside of the spring with shock rubbers . My stock spring would bottom at just the slightest bump , now with it filled solid it's prefect no bottoming and seems to have some compression feeling .
Dave and David can you post some pic when get the chance? Thanks!
 
#12
Dave, with the Century spring 4115, are you also running the inner spring? If so, does it have a Century part number?
Todd, no inner spring. I haven't rode on it yet, but it seems to be a well suited spring. I cant bottom it out by bouncing on it. Century's part number is 4115. It's only about 23 dollars, but they have a $50 min. order requirement.
 
#14
Here are the specifications of that spring. I see in other posts, some efforts at mathematics, swing arm length, ratios, and the like. I disregarded them, relying instead of individual specifications such as length, wire diameter, total coils, and ends. I also ordered two additional springs of very near specifications, but they're just too light. One of them would work with an additional inner spring. I do not like two springs, as they rub, weakening both springs.

Part #: 4115 O.D: 1.531" LENGTH: 4.25" ID: .907" RATE:1003 MAX. DEFLECTION: 0.48" MAX. LOAD: 478 LBS
WIRE DIA: 0.312" TOTAL COILS: 9.5 MATERIAL: Spring Steel ENDS: Closed Ground FINISH: Zinc Cost: $20.09
 
#15
I called Century the other day and they are out of stock on that spring with a 6-10week lead time. They suggested that I call OSH and ACE to see if they had inventory as Century distributes some springs thru that channel. Sounds like the Century route may take a while....bummer.
 
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