1/5 Scale Nitro Touring Car:

H.A.R.M. SR-1 - # 1490620 - Radio Controlled Model

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History and Info for the SR-1:

Introduced by H.A.R.M. Racing circa 2007, the 2WD SR-1 Eco chassis, was available as an entry level model - # 1490620 - or racing competition SR-1 Cup-Chassis - # 1490620CUP

The model was based on a double deck alloy plate chassis, with a gear type differential, coil spring over oil filled dampers, cardan drive-shafts and ball bearings.

Harm SR-1

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To race the HARM SR-1, it needs to be tuned to perfection for better stability, precise steering and provide enough grip to keep you on the track when going around tight bends at high speed. Even the smallest adjustment can change the feel of a car and our simple to follow instructions will guide you to the best Set-up to get you to the front and keep you there.

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Radio Controlled Model Accessories:

★ HARM SR-1 ★

★ HARM SR-1 Chassis ★

Buying a Used HARM SR-1
Touring Car (and What to look for)

There are essentially three reasons you might want to buy a used HARM SR-1 Nitro Touring Car; you may be a collector, looking to restore and display it; restore and sell for a profit; or simply restore and race an iconic vintage model. Personally, I used to get a buzz out of restoring an old clapped-out model, installing modern day electrics and maybe a few hop-ups, then showing the gang at our local club, just how competitive those old models could still be.

Cheap, pre-loved bargain models, parts and spares are always coming up for sale, but once you have made your purchase, the one thing you will always need, is an instruction manual. If not supplied with your purchase, they can often be downloaded from the HARM website, or purchased separately on eBay. With an instruction manual, any problems with your model Touring Car you may discover, can easily be fixed.

Make a General Visual Inspection

Dampers
When you receive your used HARM Touring Car, make a general visual inspection of the chassis, front and rear wishbones, suspension shock towers etc, for any broken parts that may need to be replaced. Then, take a screwdriver and box spanner and check each self tapping screw and nut for security, taking care not to over tighten.

Next, for those HARM models with oil filled shock absorbers, remove them from the chassis and dismantle the coil springs. The damper shafts should push in and pull out with a smooth action. If you feel a jolt as you change direction, this means the oil has leaked out and must be topped up. At the same time, change the O-Ring seals to prevent more leakage. Also check the damper shafts for damage. If they are scratched, change them as soon as possible.

Check the Body-Shell

If the body shell of your HARM SR-1 is broken, ripped or damaged in any way, this can be easily repaired with rubber solution glue. Also, for added protection and if available for your SR-1 model, fit an under guard to stop dirt and gravel entering the chassis.

Drive Shafts and Turnbuckles

Titanium Turnbuckles
Examine the drive shafts for wear and replace as required. If possible, change them for titanium. The steel shafts wear and bend too easily.

If you intend to race your SR-1 Touring Car model at a competitive level, I would also recommend you obtain and fit titanium pivot shafts, turnbuckles, tie rods and steering rods.

Examine the Drive System

The gearbox of your used Touring Car should be opened up to check for gear wear and lubrication. A thin coat of grease is often used on internal gears and although this is fine for basic running around on the road, if you intend to race your Touring Car at a higher level, this should be removed and replaced with racing oil (ZX1 or Teflon Oil). Of course, this should be reapplied after each race meeting.

Pinions and Spur Gears

Gears are a weakness on all Touring Car RC models. Head on collisions can easily damage the gear teeth on nylon and plastic spur gears. Heavy impacts can also loosen the nuts or self tapping screws that hold the Nitro Engine in Position, allowing the pinion gear to pull out of mesh slightly and rip the tops off the teeth on your spur gear. To minimise this possibility, fit bolts with locking nuts to the Nitro Engine mount and remember to check them for security after every two or three runs.

Don't Neglect the Ball-Joints

Ball joints always cause problems. For top level Nitro Touring Car racing, the plastic ball connectors should be checked and if deemed necessary changed after every meeting. A simple thing like a loose fitting connector popping off could easily end your race, so better safe than sorry.

Steering Servo and Servo-Saver

Servo Gears
The SR-1 steering servo is also prone to damage. In high speed crash situations, the fragile gear teeth of the servo can be broken off, rendering your expensive servo useless, so be sure to obtain a good quality "Servo Saver". Check out my Servo Information article.

Stabilizers

If body roll on your HARM SR-1 is a problem, handling can be improved with the use of stabilizers, anti roll or sway bars, stiffer tuning springs and, or, thicker silicone oil in the dampers.

Don't Forget those Bearings

If your used HARM Touring Car comes with plastic and sintered brass bushings (ring type bearings), check the shafts that run in them for wear. Dust and grit can get into these bearings and abrade the shafts. Therefore, you should replace them all with shielded ball bearings. If the model has been run with ring type bearings, you may have to change all the axles and driveshafts. For more information, take a look at my article, How to get the best from your Bearings.

Finally, good luck with your SR-1 model and good racing.

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Manufacturers and Brands Catalogued, Listed and Reviewed by RC-Scrapyard.

At present, the RC Model Manufacturers, Brands and Distributors covered by us are: ABC Hobby, Academy, Acme Racing, Agama Racing, Amewi, Ansmann Racing, ARRMA, Team Associated, Atomic RC, Axial, AYK, Bolink, BSD Racing, Capricorn, Carisma, Carson, Caster Racing, Cen, Corally, Custom Works, Durango, Duratrax, ECX - Electrix, Exceed RC, FG Modellsport, FS-Racing, FTX, Fujimi, Gmade, GS-Racing, Harm, HBX, Helion, Heng Long, Himoto Racing, Hirobo, Hitari, Hobao, Hong-Nor, Hot Bodies, HPI, HSP, Intech, Integy, Jamara, JQ Products, Kawada, Kyosho, Losi, LRP, Maisto, Mardave, Marui, Maverick, MCD Racing, Megatech, Mugen, New Bright, Nichimo, Nikko, Nkok, Ofna, Pro-Pulse, Protech, PTI, RC4WD, Redcat Racing, RJ-Speed, Robitronic, Schumacher, Seben, Serpent, Smartech, Sportwerks, Step-Up, Tamiya, Team-C Racing, Team Magic, Thunder Tiger, Tomy, Top Racing, Traxxas, Trinity, Tyco, Vaterra RC, Venom, VRX Racing, WLToys, X-Factory, Xmods, Xpress, Xray, XTM, Yankee RC, Yokomo, ZD Racing and Zipzaps.

This is an ongoing project, with new and "lost in time" RC Models and Brands being added as they are found and although most of those listed above have been covered in relative detail, some are still being researched and will be completed in the near future.

RC Information and Advice:

Hints, Tips and Information

The Importance of Suspension Droop

   When you pick up your RC model car, the suspension arms naturally drop, this is termed as Droop and should be equal from side to side, but can vary from front to rear.

   Setting the amount of droop, or suspension movement, can dramatically change the handling of your car by limiting the transfer of weight from one side of the car to the other.

   Basically, increasing the droop at the rear of the car can improve cornering grip at the front and increasing droop at the front of the car, improve cornering grip at the rear. The amount of effectiveness of this setting does in general depend on a number of other setting factors your car may have to suit your personal driving style.

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Hints, Tips and Information

Damper Pistons

   When you first build your RC model, you will sometimes find that there are a number of different pistons in the kit, with varying numbers of holes or hole sizes in them. Generally, the manufacturer will suggest one particular piston in the car manual, and may provide you with a mid range oil weight, but depending on the type of terrain you intend to race your model, their suggestion may not be the best for your needs.

   When it comes to tuning your dampers there are basically two things you need to know about pistons. "Pack" and "Static Damping".

   Pack, is the speed your damper reacts to any quick compression and can be considered to be a consequence of the size or number of holes in the piston. Smaller holes, more pack, larger holes, less pack.

   Static Damping is the amount of resistance you sense when slowly pulling or pushing the piston rod in and out of the damper.

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