This is a thread to cover how to keep an old Giant NRS going, forever. smashysmashy created a thread about customizing his NRS (https://forums.mtbr.com/26er-bikes/...ecting-my-giant-nrs-_-need-thoughts-opinions-mods-27-5-shocks-fork-1098573.html). This is a bit different as its really about keeping an old NRS ridable and maintainable. There are not many of these around, but as I have one and have done a bit of work keeping it going, I'll post my helpful hints and part sources here.
First, a bit of background on the NRS.
The NRS is one early of a Horst Link design inspired full suspension bicycles. When it was designed in the early 2000's, most full suspension bikes were fairly basic and traded ride quality for efficiency. So if it rode well, it would bob under pedaling and require a shock lockout to be an efficient climber. This was a real issue for cross country racing. So Pascal Tribotte, an avid mountain biker and a member of the Renault Sport Formula One team, convinced Giant to allow the Renault team to design a suspension for their cross country full suspension bike. They wanted a bike that was very efficient without requiring a lockout. This would provide an efficient pedaling platform with the advantages of a full suspension ride.
What they came up with was the NRS or No Resonance Suspension. Essentially the design relied on pedaling forces to extend the shock while tuning the linkages to eliminate resonance, which, left unchecked, would amplify bobbing. The sweet spot for the design was between a cadence of 45 to 90 rpm. That was the theory anyway. And they succeeded. The NRS design has the efficiency of a hard tail, but some rear suspension compliance, even under pedaling.
While the suspension lived up to the theory, in reality, the suspension design didn't provide much small bump compliance and was harsh in comparison to other designs. As well, it was not tolerant of an incorrect setup. The design required fairly precise no-sag setup by varying air pressure in the rear air shock. However, it must be remembered that the NRS was designed for cross country racing in the 2000's. Trails were generally tamer than today and efficiency was the overriding design criteria. The idea of a trail bike hadn't even occurred to anyone.
Other than the rear suspension design, the NRS was fairly conventional. Lower end models were aluminum frame construction with lower end spec'd components including rim brakes. Higher end models had first generation hydraulic disk brakes and eventually the option of carbon frames. The NRS3 was the lowest end bike with the NRS1 being the highest end aluminum framed bike. The later carbon frame bikes received NRS Air designation. NRS Team bikes had special paint jobs and were produced in aluminum.
Giant started selling the bikes in 2001 and the last model was sold in 2005. There were several tweaks along the way. The first revision was in 2002 when the rear shock mount and frame received some reinforcement. In 2004, the rear frame geometry was changed slightly and the chain stays redesigned. The rear pivot bushings changed to cartridge bearings in 2004. The shock pivot arms came in a few varieties depending on the market and spec level with some variants having multiple upper shock mounting holes to provide an option of two travel settings. Shock options varied by the model with earlier bikes receiving RockShox and later receiving Fox, depending on the market. Most of the design was standard for a mountain bike of the time. The rear hub spacing was 135mm. The front fork had a 1-1/8" steering tube diameter without taper. Stem length was long and the bars were narrow and flat for a cross country racing position. For most models, the head tube angle was 70 degrees with a seat tube angle of 72 degrees. Chain stay length was 425mm across the lineup. Wheelbase ranged from 1047mm to 1081mm. Rear travel was 85mm, all in up-travel. Front shock travel was 80mm. Depending on model spec, the bike could weigh anywhere from 24.5lbs to over 28lbs. Swapping in light weight components on a carbon frame could get a build in the 23lb range. Typical NRS1 build would be 26lbs. That's fairly light for a mass produced full suspension bike of the period.
On the higher end models, Giant was pretty cutting edge for the time. The aforementioned carbon construction in the latter half of production, hydraulic disk brakes, tubeless UST tires on Mavic rims and 27 speed drivetrains were fairly advanced for the early 2000's. Pricing ran the gamut as well, with low spec NRS3 starting just over $1000US, high end aluminum bikes around $2000US and carbon bikes approaching $4000US. So not an inexpensive bike for the time.
The bike won a number of accolades, including bike of the year in 2001 from several publications. The bike enjoyed some racing success with custom carbon prototypes built for Giant team racers such as Rune Hoydahl, Bart Brentjens and Christophe Dupouey,
In 2006 the NRS was replaced by the Anthem which introduced the new Maestro suspension design, delivering nearly the efficiency with better ride quality. The Maestro design continues in Giant's line-up to this day.
NRS Trivia:
In the US, Giant decided to license the Horst Link design from Specialized. Part of the agreement required application of stickers to the frames, before delivery, giving Specialized credit for the rear suspension. This delayed the introduction of the NRS to US markets. Many would argue that the NRS is not a pure Horst link design due to pivot locations and geometry.
Many efforts were made to soften the NRS's ride. Some riders would introduce rear sag into the system which resulted in bobbing and brake jacking. Giant even suggested introducing some sag in the later years of the NRS. After-market rocker arms were marketed to increase travel and soften the ride. The results were mixed. Cane Creek marketed a replacement shock for the NRS which was said to improve ride quality.
Giant isn't the only one who designed a suspension that counters bobbing by topping out the shock. Brian Berthold, who designed the Magic Link for Kona, now has his own brand, Tantrum, which showcases his very own Missing Link suspension deign. While vastly more complex than the NRS design, the Missing Link design allows the shock to top out, limiting bobbing under power. Of course, the Missing Link provides a vastly improved ride and is intended for a trail bike.
Weaknesses of the NRS design:
Ride quality: Some joked that NRS stood for "No Rear Suspension." The rear suspension had no down travel and pedaling forces made it even stiffer. So often the ride is compared to a hard tail. While never described a plush, the NRS always had an active rear suspension even under pedaling, but it would take a large bump to get it activated. If you are used to a hardtail, the NRS will feel familiar. It takes the edge off the largest of hits.
Rider Weight: Giant recommended a rider weight of less than 220lbs. The reason being the pressure limit of the rear shock. Giant recommended a positive air pressure of the riders weight in lbs. plus 20 psi. Most of the rear shocks available for the NRS had a positive pressure limit of 250psi, thus the weight limit recommendation.
Rear Shock Availability: Rear shocks for the NRS were specific to the NRS design. They are a dual chamber non-platform shock. There are none available new today that would work well on the NRS. Some of the shocks had both positive and negative air pressure adjustments, others had only positive air adjustments.
Next: My NRS
First, a bit of background on the NRS.
The NRS is one early of a Horst Link design inspired full suspension bicycles. When it was designed in the early 2000's, most full suspension bikes were fairly basic and traded ride quality for efficiency. So if it rode well, it would bob under pedaling and require a shock lockout to be an efficient climber. This was a real issue for cross country racing. So Pascal Tribotte, an avid mountain biker and a member of the Renault Sport Formula One team, convinced Giant to allow the Renault team to design a suspension for their cross country full suspension bike. They wanted a bike that was very efficient without requiring a lockout. This would provide an efficient pedaling platform with the advantages of a full suspension ride.
What they came up with was the NRS or No Resonance Suspension. Essentially the design relied on pedaling forces to extend the shock while tuning the linkages to eliminate resonance, which, left unchecked, would amplify bobbing. The sweet spot for the design was between a cadence of 45 to 90 rpm. That was the theory anyway. And they succeeded. The NRS design has the efficiency of a hard tail, but some rear suspension compliance, even under pedaling.
While the suspension lived up to the theory, in reality, the suspension design didn't provide much small bump compliance and was harsh in comparison to other designs. As well, it was not tolerant of an incorrect setup. The design required fairly precise no-sag setup by varying air pressure in the rear air shock. However, it must be remembered that the NRS was designed for cross country racing in the 2000's. Trails were generally tamer than today and efficiency was the overriding design criteria. The idea of a trail bike hadn't even occurred to anyone.
Other than the rear suspension design, the NRS was fairly conventional. Lower end models were aluminum frame construction with lower end spec'd components including rim brakes. Higher end models had first generation hydraulic disk brakes and eventually the option of carbon frames. The NRS3 was the lowest end bike with the NRS1 being the highest end aluminum framed bike. The later carbon frame bikes received NRS Air designation. NRS Team bikes had special paint jobs and were produced in aluminum.
Giant started selling the bikes in 2001 and the last model was sold in 2005. There were several tweaks along the way. The first revision was in 2002 when the rear shock mount and frame received some reinforcement. In 2004, the rear frame geometry was changed slightly and the chain stays redesigned. The rear pivot bushings changed to cartridge bearings in 2004. The shock pivot arms came in a few varieties depending on the market and spec level with some variants having multiple upper shock mounting holes to provide an option of two travel settings. Shock options varied by the model with earlier bikes receiving RockShox and later receiving Fox, depending on the market. Most of the design was standard for a mountain bike of the time. The rear hub spacing was 135mm. The front fork had a 1-1/8" steering tube diameter without taper. Stem length was long and the bars were narrow and flat for a cross country racing position. For most models, the head tube angle was 70 degrees with a seat tube angle of 72 degrees. Chain stay length was 425mm across the lineup. Wheelbase ranged from 1047mm to 1081mm. Rear travel was 85mm, all in up-travel. Front shock travel was 80mm. Depending on model spec, the bike could weigh anywhere from 24.5lbs to over 28lbs. Swapping in light weight components on a carbon frame could get a build in the 23lb range. Typical NRS1 build would be 26lbs. That's fairly light for a mass produced full suspension bike of the period.
On the higher end models, Giant was pretty cutting edge for the time. The aforementioned carbon construction in the latter half of production, hydraulic disk brakes, tubeless UST tires on Mavic rims and 27 speed drivetrains were fairly advanced for the early 2000's. Pricing ran the gamut as well, with low spec NRS3 starting just over $1000US, high end aluminum bikes around $2000US and carbon bikes approaching $4000US. So not an inexpensive bike for the time.
The bike won a number of accolades, including bike of the year in 2001 from several publications. The bike enjoyed some racing success with custom carbon prototypes built for Giant team racers such as Rune Hoydahl, Bart Brentjens and Christophe Dupouey,
In 2006 the NRS was replaced by the Anthem which introduced the new Maestro suspension design, delivering nearly the efficiency with better ride quality. The Maestro design continues in Giant's line-up to this day.
NRS Trivia:
In the US, Giant decided to license the Horst Link design from Specialized. Part of the agreement required application of stickers to the frames, before delivery, giving Specialized credit for the rear suspension. This delayed the introduction of the NRS to US markets. Many would argue that the NRS is not a pure Horst link design due to pivot locations and geometry.
Many efforts were made to soften the NRS's ride. Some riders would introduce rear sag into the system which resulted in bobbing and brake jacking. Giant even suggested introducing some sag in the later years of the NRS. After-market rocker arms were marketed to increase travel and soften the ride. The results were mixed. Cane Creek marketed a replacement shock for the NRS which was said to improve ride quality.
Giant isn't the only one who designed a suspension that counters bobbing by topping out the shock. Brian Berthold, who designed the Magic Link for Kona, now has his own brand, Tantrum, which showcases his very own Missing Link suspension deign. While vastly more complex than the NRS design, the Missing Link design allows the shock to top out, limiting bobbing under power. Of course, the Missing Link provides a vastly improved ride and is intended for a trail bike.
Weaknesses of the NRS design:
Ride quality: Some joked that NRS stood for "No Rear Suspension." The rear suspension had no down travel and pedaling forces made it even stiffer. So often the ride is compared to a hard tail. While never described a plush, the NRS always had an active rear suspension even under pedaling, but it would take a large bump to get it activated. If you are used to a hardtail, the NRS will feel familiar. It takes the edge off the largest of hits.
Rider Weight: Giant recommended a rider weight of less than 220lbs. The reason being the pressure limit of the rear shock. Giant recommended a positive air pressure of the riders weight in lbs. plus 20 psi. Most of the rear shocks available for the NRS had a positive pressure limit of 250psi, thus the weight limit recommendation.
Rear Shock Availability: Rear shocks for the NRS were specific to the NRS design. They are a dual chamber non-platform shock. There are none available new today that would work well on the NRS. Some of the shocks had both positive and negative air pressure adjustments, others had only positive air adjustments.
Next: My NRS
