58-59 upper fork tree

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1951 adam
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58-59 upper fork tree

#1

Post by 1951 adam »

Does anyone know the difference between the 49-57, 58-59 top tree? same cast number, slight difference in the machining on underside were stem pre load nut would rest, why? bearings didnt change till 60, just curious. also the block off plate where the steering dampner would sit, seems like most of the photos i see of 59's have steering dampners, did'nt they only use them on sidecar bikes in 59 due to handleing issues?
1950Panhead
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Re: 58-59 upper fork tree

#2

Post by 1950Panhead »

Rigid and duoglide tress differ.
I received a duo tree in a 53 basket, it would not work.
It has been awhile, duo tree may have different rake meaning tree top has to match.
Jerry
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Re: 58-59 upper fork tree

#3

Post by Panacea »

RUBONE
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Re: 58-59 upper fork tree

#4

Post by RUBONE »

The lower tree was changed to correct the rake on the new for '58 sprung frame. The stem was offset and the top tree machined to match. The '58 frame sat differently in relation to the ground causing the fork angle to change, so the trees were modified to make the actual rake angle and wheelbase correct . It had nothing to do with the bearings which were changed in '60 to allow a type with more rollers. the steering damper was stock for '58 and most of '59 when it was deemed not longer necessary and discontinued on solo machines. some later '59s come with a stainless cover and no damper. From '60 on it was only used standard on Sidecar machines however it was always available as an option .
1951 adam
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Re: 58-59 upper fork tree

#5

Post by 1951 adam »

Robbie your wealth of knowledge is amazing!, Thank you. Are there any other markings between the early duo and hydra trees...date code ect?
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Re: 58-59 upper fork tree

#6

Post by VPH-D »

Robbie,
Are you saying the trees were deraked in 58, or was the rake increased? I've never noticed this difference.
VPH-D
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Re: 58-59 upper fork tree

#7

Post by RUBONE »

VPH-D,
They were de-raked by a couple degrees. Look at the bottom of a '58 up lower tree and note that the boss for the stem was elongated and the stem hole moved forward, therefore causing the legs to move back which increased the trail. Basically the same as the offset BT springer, but moving the bottom of the stem and not the top.
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Re: 58-59 upper fork tree

#8

Post by RUBONE »

VPH-D,
They were de-raked by a couple degrees. Look at the bottom of a '58 up lower tree and note that the boss for the stem was elongated and the stem hole moved forward, therefore causing the legs to move back which increased the trail. Basically the same as the offset BT springer, but moving the bottom of the stem and not the top.
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Re: 58-59 upper fork tree

#9

Post by VPH-D »

Robbie
Thanks for explanation.
VPH-D
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Re: 58-59 upper fork tree

#10

Post by Gotnoclass »

A great example of what RUBONE is talking about can be seen on Mr. Palmer's book page 617. A factory photo of 58 prototype is built with the 57 and older glide trees. The forks are raked a couple of degrees outwards. As a comparison, check out the 1959 prototype pictures on page 621
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Re: 58-59 upper fork tree

#11

Post by UPSROD »

Actually the 58 prototype on pg.617 has adjustable forks on it.
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