NRS - Trail bike Modifications (Long Post)
I have been building up a 2002 NRS for trail bike usage, I love the way it
climbs. I thought I might share what I learned.
Stock it came with a 80mm front fork, 70 degree head angle, 12.63 bottom
bracket height and 42.0" wheelbase.
I wanted a 100mm fork. I put on a Marzocchi MX pro w/eta, Heavy but plush.
The results were 68.5 head angle, 13.13" bottom bracket and a 42.5"
wheelbase. I think the angle is so bad due to production stack up issues.
The MX fork measures 6mm longer than reported in their manual. I compared
it against an 80mm Manitou fork and found the Marzocchi to be 35mm taller.
This really killed the cornering adhesion of the front tire. I used a
straight up seatpost, shoved the saddle all the way forward and lowered the
bars. Still some corners are sketchy.
Then I installed the SGF rockers. I weigh 185# and I didn't like the 4.5"
travel position. I couldn't pump the shock up enough to suit my tastes for
bob-free performance. So, I used the 3.5" position. This resulted in
almost the same air pressure in the rear shock as I had originaly. The
result is a 69 degree head angle, 13.38" bottom bracket height, and 42.75"
The bike handles better. I actually had to move the saddle 7mm backwards
last night. Not sure if I am done yet. It rides pretty good, but I am
still not sure about the cornering. I have thought about an 80 mm fork but
I hate to give up the plush ride and the bottom bracket clearance.
The 2004 NRS has a 71 degree head angle. I think Giant finally realized
that someone would put a 100mm fork on it.
I have a 03 NRS Team frame with the 4.5 rockers and 02 Rock Shox Psylos at 100mm.
I initially found the bottom bracket a bit high but I soon go used to it. I run my Giant NRS shock (replacement for the crappy SID) at between 230psi and 250psi depending on how plush I want it.
As an experiment I set my Psylos at 80mm and put the rear at 3.75. It cornered a little bit faster but I preferred the plusher ride of the longer travel set up. I really think the 4.5 rockers make the frame alot better. It just takes a bit of time to get used to the BB height.
I also recently swapped my Psylo springs for stiffer ones and this better complements the frame than the super plushness of the originals. Less brake dive and a modded Climb it Control (no lock out but way more adjustable compression) make the fork much stiffer but still as plush (if that makes sense).
Watch the welds...I broke a 2001 frame and I weight 185lbs as well. If you're going ride it hard (is there any other way?)...just watch the welds! Luckily it did not catasrophicaly fail - it cracked around the top of the bracket that holds the shock onto the seat tube.
Giant warrantied it for a 2002 frame - I had already realized the bike was not beefy enough for my style of trail riding. Hence I now ride a 2003 AC-1.
"I may be old and fat, but at least I'm slow." - Me
Born on 2 Wheels
Hey nice bikes guys! I've had my 04 NRS 1 for about 8 and got the frame of ebay and built it up and i love it! best full Suspension! Whats the point of the rockers I have stock and I was wondering whats the difference?
"Shut up and Ride"
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Fox DHX 5.0
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thats my red stapler
a somewhat subjective question but did you break the welds cause your 185 or because of the way you ride?
Originally Posted by bikeCOLORADO
ive got a 2003 with a talas on the front granted ive only got a few rides on it but right now im riding it mostly around 100mm with out many issues
when the going gets tough the world gets reduced to one pedal stroke at a time
Answer - Combination of the two. I ride very technical XC trails with plenty of ledges, rocks, rock gardens and a few small drops. I was up to dropping about a 2.5 footer to flat pretty regularly on the NRS before it cracked. As a testament to the frame, I was about 1 week out from a big Moab trip when I noticed the crack. I asked my local shop and they said it should be OK, just check to see if it starts growing (the crack). I rode Slickrock, Amassa Rock, Flat Pass and Porc Rim pretty hard and the crack only budged about 1.5mm. I turned it in for warranty the day after I got back from Moab.
If I'd have stuck to pretty smooth singletrack I don't think it would have cracked. Add my hefty 185lbs to the techno XC riding and it ads up to a fair amount of wear and tear on any frame.
"I may be old and fat, but at least I'm slow." - Me
If I remember rightly the welds on the 2001 frames were problematic and it was fixed with a slight modification on the 2002 on models. So it should be okay. Also I tend not to do drop offs as I am a wuss.
The 4.5 rockers are an aftermarket product by a guy in your neck of the woods (USA). It gives you a choice of either 3.75" or 4.5" travel. The have the same bearings in them and made to a high standard. When fitted in the 4.5" position they increase the BB height (about 1cm from what I remember) and you need to increase the pressure in the shock to achieve the NRS no bob thing. Do a search on eBay and you should find them.
They make the bike ride plusher and the small bike compliance is far better. Some people find it does not climb quite as spritely as the 3.75 setting but I can't say I have noticed.
Overall it is a worthwhile $60 upgrade and coupled with a 100mm fork it makes it a good trail bike.
Here is a pic of the bike since its mods, even with the new mud I put on it today.
Thanks for all the info!
This is the 4th bike I have built in 4 years. I learn something more, all the time.
Some people downplay the effect of the length of the fork on head tube angle, but it seems to be important to me.
A lot of the trails in South Eastern Michigan are very tight single track. Steering precision is very important to me.
I want a bike that smooths out the rocks and roots, climbs well, is light and handles well. (I am not asking for too much???)
I just sold my VT. It is a wonderful bike. But the frame and shock were 1.5# heavier than the NRS and the NRS climbs better.
I am not a racer, but so far the NRS is pretty close to meeting my needs.
Again, Thanks for all the info.
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