The facts.
| Brand | Öhlins |
|---|---|
| Part Number | 21729-34 |
| Spring Rate | 100 N/mm |
| Free Length | 182 mm |
| Inner Diameter | 51 mm |
| Stroke | 86 mm |
| Construction | Straight |
| Finish | Powder-coated yellow |
| Country of Origin | Sweden |
DescriptionThe whole story▼
Öhlins part number 21729-34 is a shock absorber spring rated at 100 N/mm, 182 mm long with a 51 mm inner diameter. Adding a pillion or luggage changes the load enough that the standard rate stops working.
Key Features
- Straight-wound, constant rate
- Inner diameter 51 mm
- 86 mm of usable stroke
- Measured spring rate 100 N/mm
- Powder-coated yellow
- Öhlins part number 21729-34
- Free length 182 mm
Why the Rate Holds
Production has stayed in Sweden since the company was founded in 1976. The unit is rebuildable: seals, shims and oil are catalogue items, not a reason to buy a new one. The finish is applied after setting, which means the coating does not affect the rate.
Dimensions
Öhlins holds the free length at 182 mm and the inner diameter at 51 mm across this rate range, so moving up or down a rate changes nothing about the installation.
Where This Rate Belongs
Heavier riders, two-up use and track days all push the choice towards this end. A firm rate keeps the fork high in its stroke under braking, which preserves the geometry when the front is loaded hard. Support under braking improves; small-bump comfort gives a little back. A road machine spends most of its life in the first third of the fork's travel — that is the part the rate governs.
How a Rear Spring Works
On a linkage-equipped machine the wheel moves several millimetres for every millimetre the damper moves, and the spring rate has to account for that ratio. A spring that has settled in service sits shorter than new, which quietly lowers the bike and steepens the steering. Öhlins sells rear springs separately precisely because rider weight varies more than machine weight does.
Applications
This spring is chosen by its dimensions rather than by motorcycle model: check inner diameter, free length and rate against the fork it is going into. Sag figures, not feel, decide whether a rate is right. Öhlins publishes the targets for its own units. If you are replacing a sagged original, measure its free length first — a tired spring often measures several millimetres short.
Fitting
Öhlins part numbers are stamped on the packaging rather than the spring, so keep the label with the setup notes. Once fitted, ride the machine before making damping changes: the new rate alters what the clicks do. Rate and preload are separate adjustments: get the rate right first, then set sag with preload.
Road Approval
Road approval: no separate certificate. The spring changes the rate, not the construction of the fork, and is treated as a service part.
Fitting and Setup Service
Öhlins recommends that its suspension is fitted by an authorised service centre. We are one, and we do the work here: installation, servicing and a proper setup. Ask us and we will include it with the order.
Specifications
- Brand: Öhlins
- Part Number: 21729-34
- Spring Rate: 100 N/mm
- Free Length: 182 mm
- Inner Diameter: 51 mm
- Stroke: 86 mm
- Construction: Straight
- Finish: Powder-coated yellow
- Country of Origin: Sweden
FitmentWhich bikes this fits▼
Questions, one topic at a time.
Get the real shipping cost for this item to your address — the same rates as checkout.
Choose a destination and hit Estimate — we fetch the live rates for this item.
We’re based in Germany. Standard delivery goes by DHL and national postal services and takes about 2–5 days within Germany, 1–2 weeks within the EU and 2–6 weeks outside the EU. Need it sooner? Express delivery reaches most of the world within a few days — just choose it at checkout where available.
Your exact shipping cost is calculated by destination and weight and shown at checkout before you pay — no hidden fees. Express delivery is selectable at checkout where available.
Yes, we ship to over 130 countries. Prices, taxes and delivery times for your destination are calculated automatically at checkout.
Within the EU, no — our prices already include all duties and EU VAT. For deliveries outside the EU (e.g. Switzerland, the UK or the USA), your order may be subject to import duties and taxes set by your country. These are collected by the carrier when your parcel arrives, aren’t included in our prices, and are outside our control.
As soon as your parcel ships we email you a tracking link, so you can follow it all the way to your door.
On out-of-stock items you can request a delivery time or leave your email to be notified the moment it returns — just use the notification box on the product.
You have the right to cancel within 14 days of receiving your order. Register your return by email first; once it’s approved you have a further 14 days to send the goods back. Items should be unused and in their original packaging.
Register your return by email with your order number before sending anything back, and we’ll send you the return instructions. Please note: returns that aren’t registered in advance can’t be accepted.
The quickest way is to place a new order for the size you need and register a return for the original by email — just let us know it’s an exchange.
We’re sorry — that shouldn’t happen. Contact us with your order number and a photo as soon as you can, and we’ll arrange a replacement or refund right away. Faulty goods are always covered by your statutory warranty.
Refunds go back to your original payment method, usually within 3–5 working days of your return reaching our warehouse.
PayPal, all major credit and debit cards (Visa, Mastercard, American Express), Klarna (pay later and instalments), Apple Pay, Google Pay and more — all processed securely via PayPal and Mollie.
Yes. Choose Klarna at checkout to split your purchase into flexible monthly installments.
Your payment is taken when you place your order. If you choose Klarna, you pay later according to Klarna’s terms.
Every payment runs over an SSL-encrypted connection through certified providers. We never see or store your full card details.
If your order hasn’t shipped yet, contact us as soon as possible and we’ll do our best to change or cancel it.
No — you can check out as a guest. An account simply lets you track orders and reorder faster.
For customers in the EU, prices are shown including your country’s local VAT. For customers outside the EU, prices are shown without VAT — instead, your country’s import taxes and duties may apply on delivery (see the customs question).
Yes. Your invoice is attached to your order confirmation email and is also available in your account.
Yes. We’re an authorised dealer, so every product is 100% original and comes with the full manufacturer warranty.
Yes. Everything we sell is genuine and comes with the manufacturer’s warranty, on top of your statutory rights. Keep your invoice as proof of purchase and contact us if you ever need to make a claim — we’ll help you through it.
Our team is happy to help. Use the contact button below and we’ll personally help you choose the right gear or part.
Measure your head circumference about one centimetre above your eyebrows and compare it with the size chart on this page. Between sizes? Choose the smaller one — the padding beds in with use.
Yes — it’s tested and approved to the current ECE 22.06 standard and road-legal across the EU.
Most of our touring and sport helmets are Pinlock-ready and many include the insert. Check the ‘What’s in the box’ section on this page for this model.
Yes — the cheek pads are channelled so the arms of your glasses slide in comfortably.
Take out the washable lining and hand-wash it in lukewarm water. Clean the shell and visor with a soft cloth and water only — never solvents.
Our team will personally help you choose the right gear or part — around 24h for a reply.