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PostPosted: Thu Oct 11, 2018 8:42 pm 
Retro Guru

Joined: Tue Aug 21, 2018 3:43 pm
Posts: 257
Location: Cambridgeshire - flatlands (the horror, the horror)
I am an XC whippet
140lbs. 5 foot 7. 1700mm in new money.
Whippets are narrow dogs.
I am a narrow man.
I am light and I ride light.
I have many bikes.
The scariest is my AMP B3.

The frame:
Beautiful thing. Wonderful welds. The rear triangle is so flexible that I have to check that I don’t have a puncture on fast descents...the back squirms like I am running on 2.4 with no air in it. I have never had a puncture on it. It feels as if i have six every ride. Scary. But that’s nothing on the fork.

The forks:
AMP alloy forks. God knows what stresses you place on the fork if you use a disc, with all the forces going through the axle and into the fork. With V brakes, it’s obvious that when you brake at full chat, the forks legs bend at least 3cms backwards. Holy crap. That’s 3cms on a fork about 460 long. And aluminium, which is not known for tolerating big and frequent stress cycles. With V brakes, at least the deceleration point is near the top of the forks, near the crown, although of course the force needs to be transmitted to the ground via the wheel and yes, lower forks through the hub.

Right. Let’s just rehearse this. I am light, I am not placing a big stress on the bike. I am doing a tough gig down a chalky, flint strewn steep ‘n long downhill on the Downs at full bore. The back feels like it’s made from spaghetti and the front from glass tubes. It’s not confidence inspiring.

AMPs are light. They are gorgeous to look at. They pioneered the Horst Link.
They are very very scary.


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PostPosted: Thu Oct 11, 2018 9:34 pm 
Retro Guru
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Joined: Sat Aug 13, 2016 8:08 am
Posts: 709
Location: Suffolk
Have to say I don't find my B4's frighting. Havn't notice any real flex in the forks....no more than SIDs for example.


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 Post subject: Re:
PostPosted: Thu Oct 11, 2018 9:40 pm 
Retro Guru

Joined: Tue Aug 21, 2018 3:43 pm
Posts: 257
Location: Cambridgeshire - flatlands (the horror, the horror)
Gerard - that’s interesting....are you vvvvvv light?

I hadn’t googled ‘AMP fork flex’ so I did and this came up immediately...

https://singletrackworld.com/forum/topi ... rks-retro/


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 Post subject: Re:
PostPosted: Thu Oct 11, 2018 9:47 pm 
Retro Guru
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Joined: Sat Aug 13, 2016 8:08 am
Posts: 709
Location: Suffolk
No not light :facepalm: 80kg or so.
AMP always seem to get mixed response...very marmite. When I go for ride this weekend I will look more closely. I have F3xc (rim) and F4BLT(disc) forks, ride the F3 more often.


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PostPosted: Thu Oct 11, 2018 9:52 pm 
Old School Grand Master
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Joined: Thu Nov 26, 2015 7:29 pm
Posts: 4603
Location: peak district
Never really noticed extreme flex on Amp forks. Im 12 going on 14st

I will add v brakes flex most things, maybe you have loose/worn linkages. Or maybe man up and stop using the brakes so much :lol:

mark


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 Post subject: Re:
PostPosted: Thu Oct 11, 2018 9:56 pm 
Retro Guru

Joined: Tue Aug 21, 2018 3:43 pm
Posts: 257
Location: Cambridgeshire - flatlands (the horror, the horror)
Yes, I am getting the Marmite vibe - I have only ever seen one other bike on the trail using them and that was a long long time ago - with 2 thousand bikes having been given to US Police officers I am surprised we don’t see more.....


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 Post subject: Re:
PostPosted: Thu Oct 11, 2018 10:01 pm 
Retro Guru

Joined: Tue Aug 21, 2018 3:43 pm
Posts: 257
Location: Cambridgeshire - flatlands (the horror, the horror)
Mkone .... yes maybe you’re right, maybe I need to surrender to gravity and to extreme flexiness.

Linkages are all very good...it genuinely is BIG FLEX.


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 Post subject: Re:
PostPosted: Thu Oct 11, 2018 10:51 pm 
Gold Trader
Gold Trader
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Joined: Fri Jan 23, 2009 2:30 pm
Posts: 14919
Location: Surrey
I've not had a b4, various incarnations of the b2/3 and a b5. Still have a litespeed version in a box.

The b2/3 had an optional brace to improve the flexing, not sure if the b4 can take one, the b5 couldn't, but that had a beefier rear triangle.

As far as looks go, I'd say it's a close run thing between an amp and an rts as the best looking full suspension bike to date. Just my opinion.

Linkage forks are apparently making a comeback.


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 Post subject: Re:
PostPosted: Thu Oct 11, 2018 11:02 pm 
Retro Guru

Joined: Tue Aug 21, 2018 3:43 pm
Posts: 257
Location: Cambridgeshire - flatlands (the horror, the horror)
Yep, when I bought the frame (imported from Laguna CA) I ordered the additional AMP brace and fitted it. Without the brace, the rear triangle is even more noodly, but you are right, the brace works well and adds little weight.

I think I might be a bit spoilt by the latest generation of DH rigs. Which are mega stiff and also virtually useless at going any way except down.

I do appreciate the very low weight of the AMP on anything pointed skywards....


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PostPosted: Thu Oct 18, 2018 9:27 am 
Retro Guru
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Joined: Thu Oct 16, 2014 2:27 pm
Posts: 369
Location: between Earth and Sky
having a B4 with an F3XC disc (both f/r) and a Rocky The Edge (actually a B2 with an optional TWP brace for the rear) with an F2 w/ cantis I can say not all bikes are equal.
The B4 rides like a modern MTB in almost every sense, except the travel. their proprietary disc brakes function a bit flimsy, but they would benefit from a bleeding I guess...
the Rocky, on the other hand, has a torsional stiffness of a flamed chorizo even with the brace.


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