Tern GSD Bike Cover — Generations, Child Seats & Fitting

The Tern GSD is a compact longtail e-cargo bike — low step-through frame, 20in wheels, rack and mudguards fitted as standard, and a long rear deck that carries children or the shopping. Because it does that job every day it usually lives outside or by the front door, which is why most owners come to us for a rain cover rather than a garage. The BikeParka Longtail range is cut for that shape: a low, long tail that a standard bike cover will not follow. This page is about the GSD alone — for the HSD, Quick Haul and the rest of the range, see all Tern bike covers.

The choice itself is simple. The Longtail is for a GSD with no child seats fitted. The Longtail WS is the same longtail shape, cut wider and taller, for a GSD with child seats fitted. Most GSDs carry seats or a Captain’s Chair, so the WS is the usual pick — it is the cover we sell for the GSD, and that fit is confirmed by us rather than estimated.

Does the cover fit every GSD generation?

Yes. The GSD has run through three generations and the differences that matter to a cover are small ones: the bike has grown a few centimetres in length, and the rear deck and battery arrangement have changed. Overall length runs to approximately 185–192cm across Gen 1–3, comfortably inside the 210cm bike length the Longtail and Longtail WS are built to take.

Generation	Approximate length	Recommended cover
GSD Gen 1 (before 2020)	Approximately 185cm (measured at 184cm)	Longtail WS with seats fitted; Longtail without
GSD Gen 2 (2020–2023)	Approximately 185cm (derived; 130cm wheelbase)	Longtail WS with seats fitted; Longtail without
GSD Gen 3 (2024 onwards)	192cm (Tern’s published figure)	Longtail WS with seats fitted; Longtail without

The other GSD numbers worth knowing: handlebars approximately 67cm across the fitted Tern sweep riser bar, against the 80cm the longtail covers allow, and height around 115cm. Height is the variable one, because the Andros adjustable stem moves the bars through roughly 110–118cm. Only the Gen 3 length is a published Tern figure; the Gen 1 and Gen 2 lengths are a third-party measurement and a derived figure respectively, so measure your own bike if it is close to a limit.

Child seats, the Captain’s Chair and the Clubhouse

The GSD’s rear deck is rated for a captain’s chair as well as rack-mounted child seats such as the Yepp Maxi, and that extra height and width at the tail is exactly what the Longtail WS is cut for. A GSD with a Captain’s Chair fitted takes the Longtail WS; so does a GSD carrying one or two rear child seats, or the Clubhouse+ handrails. If the seats come off the bike, the standard Longtail is the closer, tidier fit over a bare deck. That is the whole condition: seats on the bike means WS, seats off means the plain Longtail.

Accessories that change the fit

A GSD is rarely a bare bike, and it is the accessories rather than the frame that take a setup outside a cover. Measure with everything fitted that you intend to leave on.

Accessory	What it does to the fit	What to do
Rear child seats or Captain’s Chair	Adds height and width at the tail	Choose the Longtail WS
Storm Shield or Clubhouse canopy	Raises overall height substantially	Fold or remove before covering
Storm Box (front cargo box)	Adds bulk and length at the front	Measure with it fitted, or take it off
Tall rear crate	Stands proud of the rear deck line	Measure with it fitted, or take it off
Front rack or tray	Adds length ahead of the bars	Measure with it fitted

Child seats, baskets, canopies, crates and other accessories can change the fit. For an unusual setup, send us your exact bike model and accessories and we’ll check before you order.

Both covers are made from waterproof, seam-sealed ripstop fabric and include lock-through openings, allowing the cover and bike to be secured together. Adjustable toggles help draw the cover in around the bike on windy days, and each cover packs into its own Stuff Sac.

Which size cover?

Two measurements decide it. Take overall length from the front tyre to the very back of the rear rack or deck, with any accessories you plan to leave on, and take handlebar width across the widest point. The Longtail and Longtail WS both take a bike up to 210cm long and 80cm across the bars, so a GSD at approximately 185–192cm and 67cm has room to spare on both. Height is the number to watch rather than length: a GSD stands around 115cm, but the Andros stem and any canopy will change that. One last thing — these figures assume the bike is stood on its wheels. A GSD can be parked vertically on its tail, and the cover is not shaped for that, so stand it horizontally before covering.

How to fit a cover to a Tern GSD

Both covers go on from the back of the bike towards the front. Start by pulling the rear of the cover over the rear deck, rack or child seats — that is the part that sets the whole fit, so seat it properly before going further. Work the cover forward along the tail, then pull the front over the handlebars. Finally, draw the toggles in so the cover sits close to the bike, and thread a lock through the lock-through openings if it is staying out overnight. The two videos below show it done on a GSD without child seats and on a GSD with seats fitted.

Fitting a cover to a Tern GSD without child seats

Fitting a cover to a Tern GSD with child seats

Tern GSD cover questions

Do I need the Longtail or the Longtail WS for my GSD?

It depends on one thing: whether child seats are on the bike. A GSD with no child seats fitted takes the Longtail. A GSD with rear child seats or a Captain’s Chair fitted takes the Longtail WS, which is the same longtail shape cut wider and taller to clear them. If the seats come on and off through the year, the WS is the safer buy, as it still covers the bike with them removed.

Does the same cover fit every Tern GSD generation?

Yes. Gen 1, Gen 2 and Gen 3 all sit at approximately 185–192cm overall, and both longtail covers take a bike up to 210cm. Handlebar width is around 67cm on all of them, against an 80cm allowance. The generation you own does not change the recommendation; what is on the rear deck does.

Does a cover fit a GSD with the Captain’s Chair fitted?

Yes — the Longtail WS is compatible with a GSD carrying the Captain’s Chair. The plain Longtail is not cut for it, so use the WS while the chair is on the bike.

Does a cover fit a GSD with the Clubhouse+ or a Storm Shield canopy?

The Clubhouse+ handrails are fine under the Longtail WS, which is cut for seat setups. A Storm Shield or Clubhouse canopy is a different matter: a canopy raises the height of the bike substantially and will take it beyond the cover, so fold or remove it before covering. If your canopy and seat combination is unusual, message us with the details and we will check first.

Can I cover a GSD with a Storm Box fitted?

Measure before you order. The Storm Box adds bulk and length ahead of the handlebars, and a bare-bike figure will not account for it. The simplest approach is to take the box off before covering; otherwise measure the bike with it fitted and check the total against the 210cm length allowance. The same applies to a tall rear crate.

How do I measure my Tern GSD before ordering?

Stand the bike on its wheels, with the accessories you intend to leave on it fitted. Measure overall length from the front tyre to the back of the rear rack or deck, then handlebar width at the widest point, then height to the top of the bars or the tallest accessory. Compare against 210cm length and 80cm bar width. If you would rather not measure, Find your fit will do the matching for you.

Will a rain cover keep a GSD dry stored outside?

That is what it is for. The fabric is waterproof, seam-sealed ripstop, so rain runs off rather than soaking through, and the toggles pull the cover in so wind is less likely to lift it. Two lock-through openings let you pass a lock through the cover so bike and cover are secured together. It is weather protection for day-to-day outdoor storage rather than a replacement for a locked shed.

What if I have a Tern HSD or Quick Haul instead?

Both are shorter than the GSD and both take a longtail cover, but the seat rules differ slightly. Our guide to all Tern bike covers has the figures for the HSD, Quick Haul, Quick Haul Long and the rest of the range.